I changed my spark plugs in my 2002 Ford F150 5.4l v8 and it is running rough. Im not sure if it is a bad cop or what to look for and Im not getting any check engine light,could someone please help???

 

Did you use dielectric grease to reinstall the COP boots? You also need to put the grease on the boot seams. Did you gap the plugs properly? Also, could be that you need to clean the MAF and the throttle body. Check the IAC hose, the elbow may be cracking.

 

Did you use Motorcraft plugs and torque them to 28 ft/lb WITHOUT antiseize compound?

 

probably have a COP going out, I'd grab a set of globals and replace them all.

How many miles are on the truck?

 

I finally did have a check engine light,I took my truck to the auto parts store and had them check the code and they found out it was the G coil that was bad so I replaced that coil and it runs great now. Thanks for all of you replies and help!!!

 

You were right about the cop going out,it was the G cop,I replaced it and it runs great now thanks!!!

 

Thanks for you help,it was a problem with the G coil and I replaced it.

 

whats a g coil? Never heard of that? truck has 8 coils 1-8 code would have been p0351-358 or p0301-308. Probably more coils will fail.

 

A=1 all the way to J=10 for the 6.8.

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i think G is the number 7 coil