I have a pretty bad problem here that I've had for a while, where my gc8 stutters and misfires like mad when on boost higher than 6 psi. i have a gfb boost controller fitted, so i can see what's going on when it stutters, and whenever i turn the duty cycle up from 0 and the boost goes past 6 odd psi there's a juddering stuttering and it doesn't really go anywhere.
I've replaced the coilpacks, the igniter, the spark plugs, the ecu for a supposed prodrive jobbie which let me get to about 8psi but smelt super rich and didnt like cold starts so i switched back and the battery, and messed with the earth, and still had no luck. i'm at a loss, there's no auto electrician nearby that will touch a scoob and i dunno what else to do, help!

 

simular problem a few years ago, timing was out by 1 tooth

 

Ive just built the engine so i dont think its off, but ill double check, can i ask which sproket was off?

 

been a while but i think it was pass side intake

 

Ive checked its timing and its all a ok, tried a second earth wire from the engine today and still got nothing, what on earth is there left ive missed. My friend put some good quality spark plugs in it just before i took it off him, are there any brands of spark plug people say to avoid? I had some bosch jobbies for my old starlet gt that it didnt like and they caused al sorts of problems.

 

I domt think you understand my problem, it doesnt have an intake leak, i checked every component when i rebuilt the engine and i know the ebc works fime as i only fitted it to see what was going on a little better. It runs pretty rich, but doesnt stutter untill the engine gets right up to full runjing temp. Can anyone tell me how the ejs sensors work as the engine runs up to temp, so i can find the dodgy one?