I have 91 Crx with a d16z6 swap. I've been temporarily using a non-vtec p75 ecu until i could get a much needed p28. Well I finally bought one, and my car has been stuttering, and having serious idling problems. I checked all my vacum lines and nothing seems to be wrong. Can anyone help me figure this out?

 

What do you mean by serious idling problems? Check the plugs at the ecu make sure theyre all tight--double check your injector wiring as well. Is this a known good ecu? do you have another car you can put it in?

 

I mean the rpms jump between 1000 and 2500 rapidly.