I have a 92 hatch with a b20vtec motor with a 1992 b16 head running a mugen chipped p28. For a while just in the morning my car wouldn't rev past 4k rpm but no codes would come up when i checked them. But it would come out of it when i shut the car off. To try and compensate for this problem i tried my friends p30 ecu. That ecu made my car barely idle and would throw a code right away. It threw MAP and O2 codes. I fixed the o2 with a new sensor and tried a different MAP but to no avail. I put my p28 back in but now it barely idles and vtec doesn't work and now it throws MAP codes. I've check the voltage on the MAP plug and everything checks out ok. Please any help would be appreciated.

Corey

 

Double check to see if your TPS and MAP plugs arent reversed.

 

I've had the motor in for over 4 months and this problem just started about a month ago. I switched the plugs around and it made it worse so that is not the problem. Somebody please help.

Corey