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possible coil, spark plug, or fuel injector problem?

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possible coil, spark plug, or fuel injector problem?

 
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Old 02-25-2012, 12:51 PM
cem1985
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possible coil, spark plug, or fuel injector problem?

I had a question if any of you have had any issues with the ignition coil going bad in an 2002 f250. Also if you could tell me how many there are to a 5.4 v8 engine.

My father keeps arguing that there are only two coils, I'm guessing 8. But could he be thinking of the core instead?

The history as of late:
What is happening now is about 4 months back we started having issues with rough idling making the truck vibrate. We replaced the spark plugs and spark plug wires then along with I think it was two coils(which my question comes in). Then ran smoothly and we did a regular oil change about a month later with high mileage type of oil and decided it was time to change the fuel filter at the oil change. Then about a month later after that we started noticing some rough idling again to point it will stall sometimes. It will idle to about 500rpm and then decide to think about quitting. We've noticed a drop in gas mileage of approx 50-100 per tank fueling up time frame(not to our driving habits).

Our car md and autozone(when check engine light was on) had said cylinder 8 misfiring. Recommends new spark plugs and a possible coil to cost almost $600 and other solutions could be fuel injectors to cost another $380.

My question is could it be a wrong gap set to cause it to do the misfiring, a fuel injector went bad, or could it really be another coil again gone bad. Any suggestions welcome here to since I really don't know what's going on with my f250 its at a little over 143,000 miles now. Would you recommend getting the fuel injectors cleaned at the same time getting the other work done since how long it takes to get the plugs replaced? Or would you recommend replacing them since it's so high in mileage already(never had the fuel injectors replaced in the vehicle's history).

 
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Old 02-25-2012, 01:10 PM
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YES...the 5.4L and V10 both have COP (coil on plug). Each spark plug has its own coil. Your 5.4L does have 8 each.

YES...coil on #8 spark plug could be bad. Just replace that coil. IMHO...if you already installed new spark plugs...then they should be good to go.

The COP install is simple and takes little time to do. If you have fuel injector issues...you would also get running lean codes.

To test if COP #8 is bad...just switch it to a known good COP. The error code should follow to #1 for example ( or where you switched it ). Again...really an easy troubleshoot method.

Good luck!


biz
 
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Old 02-25-2012, 01:26 PM
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thank you will have my husband try that when he gets off of work. Really hate to have to replace another coil but it seems like that might be the issue again since kind of feels like what happened about 3 months before when we had two replaced (coil) and went ahead with sparks since it hasn't been done in it's life of being a truck!


Do you know of why a coil could go bad? or is it a somewhat common issue in the vehicle after time.
 
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Old 02-25-2012, 01:48 PM
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Usually...yeah...mileage and time will have the COP go bad. It just happens sometimes...


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Old 02-25-2012, 04:10 PM
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What you might want to do is swap the coil from another cylinder. See if the problem stays at #8 or moves to the new cylinder. If it does, you found the problem. If not, then the COP is not the problem.

In addition to the COP, there is a boot that can also go bad.
 
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Old 02-25-2012, 04:50 PM
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It also sounds like similar issues with using non-Motorcraft spark plugs. For whatever reason, alternative brands have been known to work correctly for only a short while, then rough idle, misfires, etc., and other times seem to work just fine.

Dave
 
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Old 02-25-2012, 07:07 PM
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Originally Posted by cem1985 View Post
.......... we started noticing some rough idling again to point it will stall sometimes. It will idle to about 500rpm and then decide to think about quitting. ....
You might also want to check/clean/replace your Idle Air Control valve (IAC).
 
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Old 03-24-2012, 05:05 PM
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Thanks everyone we wound up replacing the 8th coil and the number 2 coil. We are also now getting a couple of new codes pop up but will need to start a different thread for that and should be a MUCH easier fix than this one was.
 
 
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