my mods are all bolt ons, e85, tune, 28psi,evo 9

my plugs seem to misfire under boost, but its a recuring problem because ive gone through 2 sets of used plugs, and now i just installed brand new oem ones but its doing it again.

when i change them they always work fine untill ive done a few pulls then they start misfiring again

the used sets were gapped to .022 but i didnt do anything to the oem ones

like i said they work fine for a while but then it starts again, and logging shows its not knock, and whenever i switch plugs it pulls fine

i thought brand new ones would last longer than a few pulls too but they didnt

is there anything that could be causing this recurring issue?

 

What type of plug are you using? I've had good success with NGK copper plugs gapped to .022-0.24 Have you looked at your ignition cables from you coil packs? Make sure they are not old and grounding on your valve cover. Lastly, do you have an ignition amplifier? I have an HKS DLi and it's worked great at higher boost levels.

 

ignition amplifier sounds interesting but damn expensive...im using the oem platinum iridium 7...how can i tell if my coil packs are grounding? i doubt they are old my car has 19k on the clock

 

You sure you're using evo 9 plugs and not evo 8 plugs? Seems this occurs rather frequently. Good luck though!

 

yea im sure i had to pay $50 for the oem evo 9 plugs....the 8 guys are lucky and can get colder bpr's for cheap cheap