hi, i have a 1992 civic ex stock. 200k on the motor. basically sometimes when i start the car up i have an erratic idle. like it revs up and down around 800 to 1100 rpms back and forth. i do know that a vacuum leak could cause this but i was wondering if there are any typical spots where a vacuum leak would happen. and if there is anything else that could cause this. also wondering where the best place to buy a new honda motor w/ tranny would be. any help would be appreciated.

thanks,
kevin

 

bubbles in your coolant system can cause this too, bleeding the coolant system is way easier than trying to pin point a vacuum leak.... so try that first.

 

could be tps sensor also, my brothers civic had that problem and he changed it and it was fine. My other friend changed his throttle body to and that solved the problem.... just a thought.......