Annoying Misfire! Rb25det!

[SleepingTalon]

Before I begin, I'll just say that I've searched the forums all over the net for days now, and have addressed all the possible issues that might cause this, and still no luck. I've tried swapping coils, gapping the plugs tighter, hardwired the coilpacks, replacing the ignitor, added HKS Twin Power Ignition DLI, looked for boost leaks, and the list goes on and on....NO LUCK! If I run more than 21psi, I get a misfire, less and it's ok. What else could this possibly be? The mods on the car are as follows...GT35R w/Tial 38mm WG, built shortblock, Nismo AFPR, Walbro 255 FP (Hardwired), Nismo 550's, AEM EMS dynotuned. The car has a PERFECT tune in it across the board. It's running 11.6 A/F at WOT, and the partial throttle is perfect. It's also running speed density, so no more MAF in the car. It has 3.5 bar AEM sensor, with IAT sensor. The car is making good power, right at 450whp on 22psi with pump gas (93 octane in the US). I'm not sure what else to do. Are the stock coils up to the task of 21+psi? Are splitfires any better for sustaining higher boost? What else could possibly cause a misfire like this? I've even put C16 race fuel in the car, as a shot in the dark, to see if it would smooth it out, but still nothing. Any help would be greatly appreciated.

[4drlvr]

I know this may sound dumb but mine had a similar problem. Check ur cranck angle sensor. If it in the middle or is it set to devance. Mine was on devance and was doing the whole missfire thing. Move it to advance and it was fine

Clockwise=Devance

Anticlockwise=Advance

Just though id let u know. C how u go

[azamataz]

Maybe your coils are shot, check them for any cracks. Also if i use any petrol in my rb26dett less then 96+ ron itll miss like crazy. so maybe give a tank full of higher octane fuel a go and see what happens.

[carl h]

any blowby issues?

what bout turbo being overoiled, i found on my 30r on my rb20 running a -4 feed line i had to run another restrictior due to over oiling.

it is possible some oil is getting into the intake charge and causing a miss...

[r33_racer]

on another note similar to carl h's you dont have your breathers returned into your instake like std do you? If there is any oil there it will be returning back into your intake possibly causing a miss.

[race_snooze]

your running 93 octane what the?? Try some octane booster.

I remember reading on here somewhere, about the fuel pump you are running that they run out of puff at high end.