my car has been running really crappy lately. its 89 hatch with a 91 b18a. my problom is when i start it it idles fine when its cold. when its cold it idles at 2000rpm but when warmed up it idles at a 1000rpm and bounces up to 1500rpm and falls back down to a 1000rpm. iv checked vacum hoses and my map sensor. out of ideas what it could be please help

 

i have the same problem but i believe all or most ls/vtec idles weird... we have three ls/vtec cars and all idles wildly even when timing is done with perfection, or it could possibly because our reprogrammed ecus!

 

NO car should idle like you describe. Check the IACV on your intake manifold. Usually a good cleaning to that sensor will solve the idling problem.