This is a 2003 Evo 8 (stock turbo + bolt ons + e85)
So i was running the stock evo 9 iridium plugs in my car for the past year and half. the car was on e85 for a year of that time. Back in august i switched over to ported 9 turbo with a high psi actuator I have never had any issues with spark untill just recently as it has started cooling off here in AZ . so i pulled my plugs last night and they were all gapped correctly they looked alright to me no oil residue or fouling or bad heat range speckling. So this morning i swapped in a lightly used set of NKG BPR8es 1 step colder plugs that i had laying around. These are standard plugs (not iridium) and i gapped them all the .20.

Im still getting random inconsistent bucking in different gears randomly did 3 pulls in third and nothing, then two pulls in second and both times i got one buck/pop. 4th gear on the freeway and nothing,
than a quick 3rd gear and bam another buck.


WTF....? :evil: this is driving me nuts.. is that gap too small for a standard plug?

help?

 

try opening them a little bit? i usually run .022-.024. You might have a boost leak.

 

I just did a boost leak test about a month ago, and it was holding 40psi maxing out the small air compressor i had. I did just this last week pop off two egr hoses for the solenoid and one of the other ones. but i put them both back on. ill check again to see if anything could have popped off.

 

Im gonna try re-gapping the plugs tonight down to .18 hopefully that will fix it.

 

Those EGR lines are going to haunt you. They were the cause of this same issue for me. I would start there since you are already aware of the issue lol.

 

Serioulsy evo 9 plugs in a 8 head? You hella can't do that man, the plugs are totally different. 9 plugs are like 1/2in longer than 8 plugs.

 

+1

That's not good at all, get some BPR8ES plugs for your car. Much cheaper too.

EDIT: Looking at the pictures those look like EVO8 plugs. Must be a type-o.

 

checked them all, and there all on. that was last weeks issue.

 

read the first post..

 

Wow, yeah I miss-read that one

Is this only happening when you go WOT? Could the drop in temps have you hitting boost cut? Sounds very similar to what your describing and would be affected by different gears.