Hi, i'm new to this forum- i have a 91 volvo 740 and i have an idling problem. The car drives perfectly without any problems. But sometimes jerks softly. The idle problem is this. - whenever i stop at a stop light for about 30 seconds into it. The rpm would go into about the 500s. And the engine light would come on. The car would barely stay on. (I recently took out the IAC valve and cleaned it. And it was fine after. A couple of days after, the problem happened again) *Any response would be a big help. Thanks

 

always check the last thing you worked on when a problem pops up.

 

Cleaning your Idle Air Controll Valve is not enough. Clean your throttle body as well. Its the one connected to the IAC valve. Very easy to do. Maybe take pictures before you disconnect hoses,wires,screws and things so you know how to fix them back later if you are new at doing this. If you dont know how to do it just go to youtube and search-"how to clean your throttle body"

 

+1 You can remove the intake tube then the throttle body and clean it real good. Use throttle body cleaner. Also make sure your flame trap isn't clogged and your other vacuum lines are in good shape.