I have a 98 ek hatch with a complete gsr swap. I am also running a P28 chipped and socketed ecu. I have installed a skunk 2 Intake manifold and everything else is stock. My car has been having erotic rev limiter through out the rpms. most commonly happens @ 2000 rpms and 3000 rpms. when i quarter throttle it, the car with bog in and out, as if the butter fly keeps opening and closing. But when i full throttle it, the car tends to go as normal. I have a check engine light on and it reads the o2 sensor, but i dont think the car should act that strange. can i get any info on it... please and thanks.

 

secondary o2 sensor or primary o2 sensor? the IAB doesnt affect performance that much. You can unplug it if you want but it will not cause the car to bog in and out. Check all your wiring again. Try checking ignition timing

 

It is the secondary o2 sensor, sometime the car also has a funny idol and rev limits at 4,500 rpms. it only does it when the check engine light stays on instead of shutting off when i turn the key on in acc. now when that happens usually the light will shut off than when i start it up it pops back on, but in this case sometimes i hear the relay near the glove box click but the check light stays on.

 

hrmmm.. clicking noise near the relay box? could be the main relay. Well have you tried checking for that? Open up your passenger door and there should be 1 screw on the side of the dash near the glove box. Remove that and you will find the black relay box. When you put the car on the on position do you hear fuel shooting?