okay so i had my motor built and ported by forcefed racing and i dropped it back into the fd, im about 400km on the break in of the motor and its seems to be running alright, but the problem im having it in the range between 900rpm and 3500rpm as soon as i go over a 1/4 throttle it starts to buck and studder and just doesnt want to accelerate but after its over 3500 it smooths out and boosts like it should, also on idle my wideband reads between 11 and 12 which is fine but under throttle its right down at 10 and it never gets any leaner, ive tried replacing grounding straps and all that stuff but i just cant seem to figure this one out.

 

How many miles do you have on the plugs? Have you pulled them out & looked at them? What about the age of the plug wires?

 

what all is done to this car mod wise you need to give a listing to start!

 

There are so many variables that one does not really know how to start helping you really.



Just bare in mind that 400k's is fark all and I wouldn't be wanting to throttle the car hard at all. In my run in period I general like to stay off boost, try to limit it to 1-2 psi. I know its a pain but it helps bed everything in nicely. I would also limit my RPM to 4.5 max



List of mods is a good start, and what type of EMS are you running??

 

well the plugs were fine when i pulled the old motor out i just cleaned them up with a wire brush, plug wires are also fairly new, and ive just replaced the O2 sensor with no new results, but i now have almost 1000k on the motor, and as far as the build goes its stock right now besides a street port and ive removed the OMP pump and am pre mixing