bad idel
#1
10-30-2003, 12:17 PM
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5.4 bad idel
i have a 1998 f250 light duty 5.4l engine, it is the same body style as a f150, it has 130,000 on it. Heres my problem, When i start it in the morning for the first time it startes up alright then when i put it in drive it just dies. then i just keep doing it and it finally stays going and then i can drive. It drives fine after that but when i stop it idels very bad it goes from 300 to 1000rpm back and forth, i have tried a new 02 senser, air mass flow senser, new computer, tps, and new plugs they didnt help at all.
i have no idea what to do now, someone please help me out
thanks alot
i have no idea what to do now, someone please help me out
thanks alot
Last edited by brock242424; 10-30-2003 at 01:15 PM.
#2
10-30-2003, 06:33 PM
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Clean or replace the IAC Valve.
It's too bad that you've had to spend so much trying to resolve this. In the future, keep in mind that most computer control devices on our trucks do not fail completely. Usually when you have a problem like you've experienced, it's the result of a dirty sensor or an air leak, not a faulty sensor.
It's too bad that you've had to spend so much trying to resolve this. In the future, keep in mind that most computer control devices on our trucks do not fail completely. Usually when you have a problem like you've experienced, it's the result of a dirty sensor or an air leak, not a faulty sensor.
#3
10-30-2003, 07:17 PM
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#4
10-30-2003, 07:23 PM
OMFG!
you bought all of that to fix an idle problem without ever gettin it diagnosed?
I'll put 20 bucks that says you have a vacuum leak somewhere from the passenger side pcv to the rear inlet on the intake. Replace your pcv too, its only 3 bucks. But for all that you've spent you could probably have a different engine by now.
Also you may have a lot of carbon buildup which results in similar behavior but it's gotta be extreme, you may wish to try cleaning it but check for that leak first.
Also, IAC would have been my first guess too.
you bought all of that to fix an idle problem without ever gettin it diagnosed?
I'll put 20 bucks that says you have a vacuum leak somewhere from the passenger side pcv to the rear inlet on the intake. Replace your pcv too, its only 3 bucks. But for all that you've spent you could probably have a different engine by now.
Also you may have a lot of carbon buildup which results in similar behavior but it's gotta be extreme, you may wish to try cleaning it but check for that leak first.
Also, IAC would have been my first guess too.
#5
10-30-2003, 09:52 PM
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#6
10-31-2003, 11:16 AM
when you replace the pcv valve, make sure to inspect the rubber elbow that the pcv valve plugs into. you may have to pull back the insulation to see it. this elbow becomes weak and collaspes when vacuum is applied. you need to look closely for a vacuum leak.
Does the truck only do this when it is cold?
there are actually four O2 sensors on the truck, but the computer will not recieve data from the O2 sensors until the temp hits around 600 degrees(may not be the exact temp). the computer has a preprogrammed loop that the truck uses until the O2 operating temperatures are reached. the O2 sensors tells the computer how to lean the gas going to the fuel injectors.
also, have you checked your egr valve system? if the egr valve is sticking open, then too much exhaust gas is rentering the combustion cycle and killing the truck. Has the DPFE sensor ever been replaced? once again, the DPFE senosor tells the pcm how much to open the EGR valve, and it will begin operating once the truck reaches a certain temperature. the DPFE senors is notorouis for failing.
hope this helps.
Does the truck only do this when it is cold?
there are actually four O2 sensors on the truck, but the computer will not recieve data from the O2 sensors until the temp hits around 600 degrees(may not be the exact temp). the computer has a preprogrammed loop that the truck uses until the O2 operating temperatures are reached. the O2 sensors tells the computer how to lean the gas going to the fuel injectors.
also, have you checked your egr valve system? if the egr valve is sticking open, then too much exhaust gas is rentering the combustion cycle and killing the truck. Has the DPFE sensor ever been replaced? once again, the DPFE senosor tells the pcm how much to open the EGR valve, and it will begin operating once the truck reaches a certain temperature. the DPFE senors is notorouis for failing.
hope this helps.
#7
10-31-2003, 07:08 PM
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#8
11-02-2003, 09:41 AM
mahoney22e,
i took the truck to ford, and the ac drain was leaking on the O2 sensor on bank1. i installed the ac drain hose, and replaced the O2 sensor on bank 1. i haven't had the rough idle yet. the truck at times doesn't even seem as if it is running. of course the idle doesn't stay that smooth all the time. it still surges somewhat, but hasn't dropped below 700 rpm's yet. the engine seems a bit more sluggish though. i'm thinking of changing the bank2 upstream O2 sensor also. would probably help the idle even more, and cure up some lack of power issue.
did you ever change your second upstream sensor?
i took the truck to ford, and the ac drain was leaking on the O2 sensor on bank1. i installed the ac drain hose, and replaced the O2 sensor on bank 1. i haven't had the rough idle yet. the truck at times doesn't even seem as if it is running. of course the idle doesn't stay that smooth all the time. it still surges somewhat, but hasn't dropped below 700 rpm's yet. the engine seems a bit more sluggish though. i'm thinking of changing the bank2 upstream O2 sensor also. would probably help the idle even more, and cure up some lack of power issue.
did you ever change your second upstream sensor?
#9
11-02-2003, 06:29 PM
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plug.
no not yet i need to though. i had my plugs and wires changed two weeks ago. haven't noticed any difference. i think i am going to change the bank 2 o2 sensor as well and clean the egr. i am debating replacing the dpfe as well. i have heard that ford has had major issues with the dpfe. not sure what they cost but if they are reasonable i will replace. that is all i am going to do before x-mas. if the rough idel is still there then i will have to live with it. i was wanting to spend some of this money on mods but at the time the rough idel fix was more pressing to me. it is losing priority really fast. ... how is the family? hope all is well. let me know if you figure something out.
no not yet i need to though. i had my plugs and wires changed two weeks ago. haven't noticed any difference. i think i am going to change the bank 2 o2 sensor as well and clean the egr. i am debating replacing the dpfe as well. i have heard that ford has had major issues with the dpfe. not sure what they cost but if they are reasonable i will replace. that is all i am going to do before x-mas. if the rough idel is still there then i will have to live with it. i was wanting to spend some of this money on mods but at the time the rough idel fix was more pressing to me. it is losing priority really fast. ... how is the family? hope all is well. let me know if you figure something out.