Misfire ad nauseum
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Misfire ad nauseum
'98 F150, 4.6/auto, 140k miles
Came back from out of town to a dead battery and low gas tank. Tried starting with my charger- no luck. Charged overnight and it started fine the next day. Drove 10 miles - everything good. Two hours later restarted and got flashing check engine light and heavy misfire at idle and under load. Got gas on way home. Next day disconnected battery to reset idle and then had misfire only under load. CEL alternated between flashing and solid for next 40 miles of occasional driving and gas mileage was almost half normal. Now misfire seems to be gone but CEL is on solid and gas mileage still seems excessive. Will check wires and plugs tommorrow and have codes checked. Any guesses?
Came back from out of town to a dead battery and low gas tank. Tried starting with my charger- no luck. Charged overnight and it started fine the next day. Drove 10 miles - everything good. Two hours later restarted and got flashing check engine light and heavy misfire at idle and under load. Got gas on way home. Next day disconnected battery to reset idle and then had misfire only under load. CEL alternated between flashing and solid for next 40 miles of occasional driving and gas mileage was almost half normal. Now misfire seems to be gone but CEL is on solid and gas mileage still seems excessive. Will check wires and plugs tommorrow and have codes checked. Any guesses?
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Joined: Jun 2002
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From: Under the flightpath of old ORD 22R
sirnose,
The last similar incident to this ( I am guessing here without the code that was set ) was a plug replacement, and when the member put the plug wire back on, he put dielectric grease on it.
The blinking and stead state CEL ( if from the mis-fire alone ) are when noted in the post as well.
This is all a guess without the code, but I am working from the mis-fire symptom, there could actually be another code set, and maybe a plugged EGR is the cause ( with another code then P0300 set ), but this is all pontification without the code numerbs mind you ( I don't want to send you off on a wild goose chase replacing things that might not be the problem ).
Take a read through this post, if you have code number, it would tell you which plug / wire / coil pack to check first.
https://www.f150online.com/forums/sh...&postid=831892
Good luck, let us know if you get the code number, and if it is not a P030x number, or what happened with you checking the plugs and wires.
Steve
The last similar incident to this ( I am guessing here without the code that was set ) was a plug replacement, and when the member put the plug wire back on, he put dielectric grease on it.
The blinking and stead state CEL ( if from the mis-fire alone ) are when noted in the post as well.
This is all a guess without the code, but I am working from the mis-fire symptom, there could actually be another code set, and maybe a plugged EGR is the cause ( with another code then P0300 set ), but this is all pontification without the code numerbs mind you ( I don't want to send you off on a wild goose chase replacing things that might not be the problem ).
Take a read through this post, if you have code number, it would tell you which plug / wire / coil pack to check first.
https://www.f150online.com/forums/sh...&postid=831892
Good luck, let us know if you get the code number, and if it is not a P030x number, or what happened with you checking the plugs and wires.
Steve
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Had Autozone check code - 304 - plug #4. Engine still running fine at this point so will wait 'till it acts up again to test plug, lead and coil pack. Checking previous posts shows this to be a fairly common problem - am I wrong?
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Joined: Jun 2002
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Likes: 10
From: Under the flightpath of old ORD 22R
sirnose,
It can be a common one, I would not say it happens all the time.
There are tons that don't get misfires at all in 100K miles ( check the 100K thread ).
Did you disconnect the battery to clear the CEL, or did they clear it for you ?
If you want there are several low cost DTC scaners that you can get, so you don't need to go to AutoZone to get the DTC.
Actron makes a Ford only scanner ( does not clear individual DTC), for ~ $ 45.00 MSRP. I think Sears HW and AutoZone carry this ( www.actron.com )
There is also an Equis ( sp ? ) and others if you search here on the term scan you might catch them all, or search via Google for DTC scaner or DTC reader.
Good luck
Steve
It can be a common one, I would not say it happens all the time.
There are tons that don't get misfires at all in 100K miles ( check the 100K thread ).
Did you disconnect the battery to clear the CEL, or did they clear it for you ?
If you want there are several low cost DTC scaners that you can get, so you don't need to go to AutoZone to get the DTC.
Actron makes a Ford only scanner ( does not clear individual DTC), for ~ $ 45.00 MSRP. I think Sears HW and AutoZone carry this ( www.actron.com )
There is also an Equis ( sp ? ) and others if you search here on the term scan you might catch them all, or search via Google for DTC scaner or DTC reader.
Good luck
Steve