I have a 1991 integra, just completely rebuilt the engine with performance pistons and racing cams i replaced all necessary parts, engine ran great firsttime it was started except the idle fluctuates anywhere from 750-2000rpms and sometimes goes so low it stalls, ive sawpped out different tps, iac and map sensors and done all the necessary checks but it still is happening, if anyone has any information plaease reply.

 

have you checked for any vaccum leaks. or pcv valve damaged. try pinching off the pcv valve and see if idle stabalizes.

 

sounds like a coolant bubble if you ask me

try burpin your coolant