Bought an 04 kj 3.7 from my woman's ford dealership they got in on trade. The
Kj passed safety and emissions testing with flying colours. Day two of owning it (214000 Kms) it started jumping and jimming and rocking all over the darn place. I plugged the obd2 scan tool in it and it reported misfire cylinder 6. Needless to say I was pissed. So I thought maybe I shoul grab some new plugs. I read somewhere that the gap should be 0.040 thousandths. Pulling the old plugs out I found they were copper ngk's with a gap of 0.070. They were a little whitish but no big deal, I was satisfied that they weren't soaked in oil so the new plugs went in and half a bottle of seafoam went into the tank (just in case it was the injector)


Literally as soon as the key was turned, the problem disappeared. I should also mention that I put in ngk coppers cause that is all the parts store had and I wasn't driving around with a misfiring cylinder all night to find some champions. Should also mention I got the vhicle for 2k in immaculate condition.

Yeah, the copper NGK plugs are the factory OEM ones and work well. With an 070 gap they were in there way too long. (should be changed every 30K for best results and have an 040 gap)

Glad it fixed your problem.

_________________
05 BLACK KJ - 42RLE & NP242
Skids, Hooks, Bent Rock Rail, Lifted, A/T's, etc.
NY and PA and Florida ONF Special Custom Organic Trail Rash