98 F150 4.6 misfiring badly
#1
11-29-2006, 08:16 AM
98 F150 4.6 misfiring badly
I copied and pasted this from another post that seemed to be abandoned...my truck has exact same symptoms...
Ok, here are the symptoms. This all started within a block of fueling up one night about a week ago. Vehicle in question is a 98 F150 ex Cab 4x4 with the 4.6.
1) Rough idle. Although not always. Sometimes it's rough, sometimes smooth as silk. Go figure.
2) Constant and sometimes blinking CEL.
3) Bad shuddering at pretty much every speed. I mean bad, like it's trying to rattle my teeth loose. Thing feels like it's running on about 4 cylinders. Smooths out decently at rpms above 2100 or so. Only shudders under light acceleration or cruising, though. Whenever you put your foot in it or ease off it the shudder goes away.
4) Intermitent ping. Ping seems to only happen at freeway speeds and only under light acceleration.
So I figured this must have had something to do with the fuel up since it happened right after. Checked my gas cap when I got home and found the seal torn. Replaced it the next morning and cleared the ecu. The CEL went away for a day or so but the problem remained. I then figured I must have stired up some crap off the bottom of the tank and plugged up my fuel filter so I changed it but that did absolutely nothing. So now what?
I'm looking at plugs, coil pack, dirty/bad maf, etc. Any ideas? Im super pressed on time for the moment so if anyone has and idea of the most likely culprit I'd love to know. Thanks guys
Ok, here are the symptoms. This all started within a block of fueling up one night about a week ago. Vehicle in question is a 98 F150 ex Cab 4x4 with the 4.6.
1) Rough idle. Although not always. Sometimes it's rough, sometimes smooth as silk. Go figure.
2) Constant and sometimes blinking CEL.
3) Bad shuddering at pretty much every speed. I mean bad, like it's trying to rattle my teeth loose. Thing feels like it's running on about 4 cylinders. Smooths out decently at rpms above 2100 or so. Only shudders under light acceleration or cruising, though. Whenever you put your foot in it or ease off it the shudder goes away.
4) Intermitent ping. Ping seems to only happen at freeway speeds and only under light acceleration.
So I figured this must have had something to do with the fuel up since it happened right after. Checked my gas cap when I got home and found the seal torn. Replaced it the next morning and cleared the ecu. The CEL went away for a day or so but the problem remained. I then figured I must have stired up some crap off the bottom of the tank and plugged up my fuel filter so I changed it but that did absolutely nothing. So now what?
I'm looking at plugs, coil pack, dirty/bad maf, etc. Any ideas? Im super pressed on time for the moment so if anyone has and idea of the most likely culprit I'd love to know. Thanks guys
#2
11-29-2006, 10:11 AM
My Mom's old Dodge Durango did exactly what you described. It turned out to be a bad crankshaft position sensor. It's best to go ahead and get your trouble codes read with a scanner. The code should still be stored in the E.C.U. even after the light went off according to my reading here on this website.
#3
11-29-2006, 10:22 AM
Originally Posted by Peacemaker
My Mom's old Dodge Durango did exactly what you described. It turned out to be a bad crankshaft position sensor. It's best to go ahead and get your trouble codes read with a scanner. The code should still be stored in the E.C.U. even after the light went off according to my reading here on this website.
#4
11-29-2006, 12:45 PM
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When you first cleared the ECU, did you read the stored codes then or was this from the second time? What was the exact code they pulled?
There's lots of info on this site about plugged EGR ports on the intake. I have also read about cracked vacuum lines on the EGR and/or PCV loops. I'd recommend searching on EGR or Rough Idle, and you'll get alot to read. Also post the actual code you pulled as there have been some mis-interpretations!
It sounds like your engine does not have the COP ignition but rather the coil-packs. You may have a bad coil pack, you may also have a bad wire. It's not too difficult to fracture a wire internally by popping it off the plug! I've also read alot on here about aftermarket/third party ignition components just not working well on these engines...
There's lots of info on this site about plugged EGR ports on the intake. I have also read about cracked vacuum lines on the EGR and/or PCV loops. I'd recommend searching on EGR or Rough Idle, and you'll get alot to read. Also post the actual code you pulled as there have been some mis-interpretations!
It sounds like your engine does not have the COP ignition but rather the coil-packs. You may have a bad coil pack, you may also have a bad wire. It's not too difficult to fracture a wire internally by popping it off the plug! I've also read alot on here about aftermarket/third party ignition components just not working well on these engines...
#5
11-29-2006, 01:57 PM
Originally Posted by K.C.
When you first cleared the ECU, did you read the stored codes then or was this from the second time? What was the exact code they pulled?
There's lots of info on this site about plugged EGR ports on the intake. I have also read about cracked vacuum lines on the EGR and/or PCV loops. I'd recommend searching on EGR or Rough Idle, and you'll get alot to read. Also post the actual code you pulled as there have been some mis-interpretations!
It sounds like your engine does not have the COP ignition but rather the coil-packs. You may have a bad coil pack, you may also have a bad wire. It's not too difficult to fracture a wire internally by popping it off the plug! I've also read alot on here about aftermarket/third party ignition components just not working well on these engines...
There's lots of info on this site about plugged EGR ports on the intake. I have also read about cracked vacuum lines on the EGR and/or PCV loops. I'd recommend searching on EGR or Rough Idle, and you'll get alot to read. Also post the actual code you pulled as there have been some mis-interpretations!
It sounds like your engine does not have the COP ignition but rather the coil-packs. You may have a bad coil pack, you may also have a bad wire. It's not too difficult to fracture a wire internally by popping it off the plug! I've also read alot on here about aftermarket/third party ignition components just not working well on these engines...
#6
11-29-2006, 02:18 PM
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Bummer about the broken bolt on the EGR valve! I think I read here that someone else had the same issue.
Two things for ya - See if you can get the actual codes and post them here. Lots of good folks out there that can help interpret them correctly. Sometimes you have to look at what the code says the problem is then look at the various things that could cause it to throw that code. Plus there's more than one code for both EGR and cylinder misfire!!! Taking a guess and randomly throwing part$ at it may end up working, but will likely just cost you extra $$ while still having the problem.
As I stated earlier I think the majority of the EGR problems are due to clogged orifices or ports in the throttle body (intake) or vacuum leaks. Carbon builds up and causes a restriction so the EGR flow sensor (DPFE) does not see the pressure differential that it's looking for across the restrictor (labelled 'orifice' on the digram).
Here is a schematic that JBREW posted on another thread that shows the flow path the sensor is monitoring:
In fact, I would recommend that you scroll down the engine forum and read the thread titled "EGR - Can of Worms". You will get pics and how-to's, etc. Follow the links to see how it's supposed to be done and read the successes of the others! That way even if you don't have the confidence to tackle the job yourself you will have the knowledge that you can take to your mechanic so you can specify exactly what you want to have done (i.e., not just a simple "clean the throttle body")
As for the misfire, again you need to get the specific code as it may be a simple misfire (plug or wire) or it may be something else. (BTW, a vacuum leak can cause a misfire also...)
If the AZ guys didn't clear the codes they are still there, or if the CEL has come on again it has them back again (hopefully the same ones!). In my book it's kind of irresponsible for the AZ sales person to give you half the info you need and then sell you some parts. If you need to, just "rent" the code reader from them. They basically sell it to you then refund your money when you bring it back. Then you can play with it yourself, get all the info, make an educated guess and see if that fixes it.
Hope you get it figured out - we're here to help!
Two things for ya - See if you can get the actual codes and post them here. Lots of good folks out there that can help interpret them correctly. Sometimes you have to look at what the code says the problem is then look at the various things that could cause it to throw that code. Plus there's more than one code for both EGR and cylinder misfire!!! Taking a guess and randomly throwing part$ at it may end up working, but will likely just cost you extra $$ while still having the problem.
As I stated earlier I think the majority of the EGR problems are due to clogged orifices or ports in the throttle body (intake) or vacuum leaks. Carbon builds up and causes a restriction so the EGR flow sensor (DPFE) does not see the pressure differential that it's looking for across the restrictor (labelled 'orifice' on the digram).
Here is a schematic that JBREW posted on another thread that shows the flow path the sensor is monitoring:
In fact, I would recommend that you scroll down the engine forum and read the thread titled "EGR - Can of Worms". You will get pics and how-to's, etc. Follow the links to see how it's supposed to be done and read the successes of the others! That way even if you don't have the confidence to tackle the job yourself you will have the knowledge that you can take to your mechanic so you can specify exactly what you want to have done (i.e., not just a simple "clean the throttle body")
As for the misfire, again you need to get the specific code as it may be a simple misfire (plug or wire) or it may be something else. (BTW, a vacuum leak can cause a misfire also...)
If the AZ guys didn't clear the codes they are still there, or if the CEL has come on again it has them back again (hopefully the same ones!). In my book it's kind of irresponsible for the AZ sales person to give you half the info you need and then sell you some parts. If you need to, just "rent" the code reader from them. They basically sell it to you then refund your money when you bring it back. Then you can play with it yourself, get all the info, make an educated guess and see if that fixes it.
Hope you get it figured out - we're here to help!
Last edited by K.C.; 11-29-2006 at 02:25 PM.
#7
11-29-2006, 02:40 PM
drtnshtr,
97 and 98 trucks as you know are unique. They have the earlier computer and plug wires in stead of COP. The blinking CEU is always a misfire. Most likely a bad plug wire or the wire is grounding to the block. You can probably correct by reaching back to plug 8 and push the wire on tight. Sometimes you can have a fowled plug but that is rare. Dielectric grease will help but you may want to consider new wires. At lease you know what wire/plug to look at.
Good luck
97 and 98 trucks as you know are unique. They have the earlier computer and plug wires in stead of COP. The blinking CEU is always a misfire. Most likely a bad plug wire or the wire is grounding to the block. You can probably correct by reaching back to plug 8 and push the wire on tight. Sometimes you can have a fowled plug but that is rare. Dielectric grease will help but you may want to consider new wires. At lease you know what wire/plug to look at.
Good luck
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#8
11-29-2006, 06:58 PM
Hi !!
This is easy - swap your ignition for new - shop eBay and find a deal - or wait until DEC 14 and I'll set you up a new top end , that will fix her for sure.
I must be feeling generous -
I'm only posting this once right here because I capitalize and purchase all I can, quite a few friends at 4Lakes4Wheelers Michigan.
danimal5737 (eBay seller) He acquires brand new Romeo plant motors that were built , but never hot fired or installed in vehicles. He parts the motors out and has to sell as used because the parts have been bolted to the motors.
He practically gives the crap away , but won't he won't part with the block ,manifolds , heads - everything on top he sells. The smoocher won't let me buy outright -he wants to sell on ebay.
Engines he's acquiring next month - 2000 model 4.6 Crown Vic motors. Same as last year - fixed up my 98 5.4 with updated type 3 injectors from these motors and Ford COP's as well.
That doesn't help your 98 , but replace you coil pacs and you'll be off to good start - get rid or the EGR , you'll still pass emissions - plug it!!
:santa:
This is easy - swap your ignition for new - shop eBay and find a deal - or wait until DEC 14 and I'll set you up a new top end , that will fix her for sure.
I must be feeling generous -
I'm only posting this once right here because I capitalize and purchase all I can, quite a few friends at 4Lakes4Wheelers Michigan.
danimal5737 (eBay seller) He acquires brand new Romeo plant motors that were built , but never hot fired or installed in vehicles. He parts the motors out and has to sell as used because the parts have been bolted to the motors.
He practically gives the crap away , but won't he won't part with the block ,manifolds , heads - everything on top he sells. The smoocher won't let me buy outright -he wants to sell on ebay.
Engines he's acquiring next month - 2000 model 4.6 Crown Vic motors. Same as last year - fixed up my 98 5.4 with updated type 3 injectors from these motors and Ford COP's as well.
That doesn't help your 98 , but replace you coil pacs and you'll be off to good start - get rid or the EGR , you'll still pass emissions - plug it!!
:santa:
#10
11-30-2006, 12:05 AM
Originally Posted by WLF
drtnshtr,
97 and 98 trucks as you know are unique. They have the earlier computer and plug wires in stead of COP. The blinking CEU is always a misfire. Most likely a bad plug wire or the wire is grounding to the block. You can probably correct by reaching back to plug 8 and push the wire on tight. Sometimes you can have a fowled plug but that is rare. Dielectric grease will help but you may want to consider new wires. At lease you know what wire/plug to look at.
Good luck
97 and 98 trucks as you know are unique. They have the earlier computer and plug wires in stead of COP. The blinking CEU is always a misfire. Most likely a bad plug wire or the wire is grounding to the block. You can probably correct by reaching back to plug 8 and push the wire on tight. Sometimes you can have a fowled plug but that is rare. Dielectric grease will help but you may want to consider new wires. At lease you know what wire/plug to look at.
Good luck
it was 2.5 yrs ago:o I wanted new motorcraft plug wires but the $75 Bosch wires are lifetime warranty and I keep getting free wires every couple of years...I know I know..if i get motorcraft wires i dont have to replace every 2-3 yrs....too late now...well, i put the new wires on tonight and drove it for a while and really got on the gas pedal a few times...Truck runs great again 
....243K miles and this baby still gets up to 90mph very quickly
....Ok now I need to get working on plugging this EGR and going back to AZ to get my codes erased...if i plug the EGR and get codes erased will the EGR code just come right back on???
#11
11-30-2006, 08:17 AM
Originally Posted by drtnshtr
I called AZ today to find exact date I installed wires last because I was positive it was last summer.... it was 2.5 yrs ago:o I wanted new motorcraft plug wires but the $75 Bosch wires are lifetime warranty and I keep getting free wires every couple of years...I know I know..if i get motorcraft wires i dont have to replace every 2-3 yrs....too late now...well, i put the new wires on tonight and drove it for a while and really got on the gas pedal a few times...Truck runs great again ....243K miles and this baby still gets up to 90mph very quickly ....Ok now I need to get working on plugging this EGR and going back to AZ to get my codes erased...if i plug the EGR and get codes erased will the EGR code just come right back on???
it was 2.5 yrs ago:o I wanted new motorcraft plug wires but the $75 Bosch wires are lifetime warranty and I keep getting free wires every couple of years...I know I know..if i get motorcraft wires i dont have to replace every 2-3 yrs....too late now...well, i put the new wires on tonight and drove it for a while and really got on the gas pedal a few times...Truck runs great again ....243K miles and this baby still gets up to 90mph very quickly ....Ok now I need to get working on plugging this EGR and going back to AZ to get my codes erased...if i plug the EGR and get codes erased will the EGR code just come right back on???Actually Boch makes good wires - surprized that they fail and your lucky it's running good with a tired ingnition , it will fail again soon , sorry but once they get coruppted they are just in and out with problems.
No sense in going further until you clean your TB it's pointless.
#12
11-30-2006, 09:44 AM
drtnshtr,
Just so you know, your engine will run better with the EGR operational. If you plug it you will loose performance and mileage. The EGR code may clear with the other problems being corrected. Just disconnect the battery for 10 mins with the high beams on and clear the computer. If you get no codes then clamp the broken stud on the EGR with one of those mini C clamps and drive away. If the code comes back you probably have the infamous clogged EGR ports. Pull it apart; you may be able to get a hold of the broken stud with vise grips. If not then just drill it out, clean out the ports (do a search here) and drive happily ever after…
Just so you know, your engine will run better with the EGR operational. If you plug it you will loose performance and mileage. The EGR code may clear with the other problems being corrected. Just disconnect the battery for 10 mins with the high beams on and clear the computer. If you get no codes then clamp the broken stud on the EGR with one of those mini C clamps and drive away. If the code comes back you probably have the infamous clogged EGR ports. Pull it apart; you may be able to get a hold of the broken stud with vise grips. If not then just drill it out, clean out the ports (do a search here) and drive happily ever after…
#13
11-30-2006, 11:08 AM
Originally Posted by WLF
drtnshtr,
Just so you know, your engine will run better with the EGR operational. If you plug it you will loose performance and mileage. The EGR code may clear with the other problems being corrected. Just disconnect the battery for 10 mins with the high beams on and clear the computer. If you get no codes then clamp the broken stud on the EGR with one of those mini C clamps and drive away. If the code comes back you probably have the infamous clogged EGR ports. Pull it apart; you may be able to get a hold of the broken stud with vise grips. If not then just drill it out, clean out the ports (do a search here) and drive happily ever after…
Just so you know, your engine will run better with the EGR operational. If you plug it you will loose performance and mileage. The EGR code may clear with the other problems being corrected. Just disconnect the battery for 10 mins with the high beams on and clear the computer. If you get no codes then clamp the broken stud on the EGR with one of those mini C clamps and drive away. If the code comes back you probably have the infamous clogged EGR ports. Pull it apart; you may be able to get a hold of the broken stud with vise grips. If not then just drill it out, clean out the ports (do a search here) and drive happily ever after…
#14
11-30-2006, 11:09 AM
Originally Posted by jbrew
Actually Boch makes good wires - surprized that they fail and your lucky it's running good with a tired ingnition , it will fail again soon , sorry but once they get coruppted they are just in and out with problems.
No sense in going further until you clean your TB it's pointless.
No sense in going further until you clean your TB it's pointless.
#15
12-01-2006, 12:05 PM
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Originally Posted by drtnshtr
I copied and pasted this from another post that seemed to be abandoned...my truck has exact same symptoms...
Ok, here are the symptoms. This all started within a block of fueling up one night about a week ago. Vehicle in question is a 98 F150 ex Cab 4x4 with the 4.6.
1) Rough idle. Although not always. Sometimes it's rough, sometimes smooth as silk. Go figure.
2) Constant and sometimes blinking CEL.
3) Bad shuddering at pretty much every speed. I mean bad, like it's trying to rattle my teeth loose. Thing feels like it's running on about 4 cylinders. Smooths out decently at rpms above 2100 or so. Only shudders under light acceleration or cruising, though. Whenever you put your foot in it or ease off it the shudder goes away.
4) Intermitent ping. Ping seems to only happen at freeway speeds and only under light acceleration.
So I figured this must have had something to do with the fuel up since it happened right after. Checked my gas cap when I got home and found the seal torn. Replaced it the next morning and cleared the ecu. The CEL went away for a day or so but the problem remained. I then figured I must have stired up some crap off the bottom of the tank and plugged up my fuel filter so I changed it but that did absolutely nothing. So now what?
I'm looking at plugs, coil pack, dirty/bad maf, etc. Any ideas? Im super pressed on time for the moment so if anyone has and idea of the most likely culprit I'd love to know. Thanks guys
Ok, here are the symptoms. This all started within a block of fueling up one night about a week ago. Vehicle in question is a 98 F150 ex Cab 4x4 with the 4.6.
1) Rough idle. Although not always. Sometimes it's rough, sometimes smooth as silk. Go figure.
2) Constant and sometimes blinking CEL.
3) Bad shuddering at pretty much every speed. I mean bad, like it's trying to rattle my teeth loose. Thing feels like it's running on about 4 cylinders. Smooths out decently at rpms above 2100 or so. Only shudders under light acceleration or cruising, though. Whenever you put your foot in it or ease off it the shudder goes away.
4) Intermitent ping. Ping seems to only happen at freeway speeds and only under light acceleration.
So I figured this must have had something to do with the fuel up since it happened right after. Checked my gas cap when I got home and found the seal torn. Replaced it the next morning and cleared the ecu. The CEL went away for a day or so but the problem remained. I then figured I must have stired up some crap off the bottom of the tank and plugged up my fuel filter so I changed it but that did absolutely nothing. So now what?
I'm looking at plugs, coil pack, dirty/bad maf, etc. Any ideas? Im super pressed on time for the moment so if anyone has and idea of the most likely culprit I'd love to know. Thanks guys
I have a 97' F-150 5.4 4x4. It did the same thing. I replaced the plugs and one injector that I thought was bad. This fixed it. Have you changed the plugs recently?
