2003 Airtrek Turbo - engine problem help
 

Good Day from NZ. :)

First time poster, but been reading alot from here.
I have a 2003 Airtrek Turbo which has been modified from stock to basically a tuned wagon close to an Evo 9. I'll list the mods at the end of the post/problem.

Basically, the car now boosts to 24psi. A few months beforehand, I had problems with 1 coil, and a set of plugs. Yeah, misfiring, being jerky when driving and such. So these got replaced, but this is where things got weird.

The stock boost is at 16psi or so around that mark. Anything about 16psi, it just starts to feel like its misfiring, being jerky, kinda like the original problems of the coils/plugs. But this is only ABOVE 16psi. Anything below that, its fine. Cruises nicely. I took it to the local tuner shop here, and put it on the dyno. They said that the ECU is locked for some reason (it was ECUflashed by the previous owner) so they couldn't fiddle with it, but it sounded like another coil. So i got an aftermarket coil, new plugs and new leads just in case, but its still there!.

Im so lost at to what to do now. If anyone could give an insight or maybe had this problem before, a suggestion would be good :)

Here is the list of mode, and also a couple of pics :)

Manual conversion
Evo 4 gearbox and flywheel
Exedy HD clutch kit
Evo 9 TD05HRA1610.5T
Evo 7 exhaust manifold / dump pipe
Rage 3.0" Evo front pipe (custom fit)
Stainless 3.0" pipe (catless) to AdrenalinR resonator, and rear muffler
Evo 6 intake
Silicon intake pipe
HKS filter
Custom intercooler piping
Front mount IC
FIC 650cc injectors
Evo 8 cams
EGR delete
Walbro 255 fuel pump
GFB Response BOV
GFB Boost Tap
Custom ECUflash tune, currently making approx 290WHP on 22psi boost
BC Gold coilovers
Advanti Geneva 18" wheels
Evo 4 / VR4 front rotors (296mm) and 2 pot calipers (vs 276mm Airtrek rotors)
Custom front Raliart style grill

What plugs did you get? And what gap?