Greetings all
 

Hi everybody, picked up my first GM car today, an '88 oldsmobile cutlass ciera with the 3.8 v6. She drives like a cloud and has the power to boot, only problem is a bumpy idle that I can't seem to sort out. Help would be greatly appreciated!

Welcome to the site. Start with checking for a vacuum leak.

CieraGuy, welcome to GMForum

Take a look around and enjoy the stay!

No vacuum leaks, checked w/ propane. The computer keeps reading a coolant temp. sensor high. Replaced the sensor, cleared the code, ECM still sets the code and car still runs bumpy at idle.

Could be dirty injectors or bad fuel filter, Problem with the PCV valve or EGR, or dirty throttle body. Could also be worn out spark plugs, old plug wires, or weak coil(s). That should give you a good list to check.

Injectors have been cleaned with cleaner and o-rings replaced, pcv valve replaced, egr valve working properly, plugs and wires recently changed, have not checked the throttle body yet. Replaced fuel filter and air filter, cleaned fuel lines with cleaner. It all points back to the coolant temp. sensor, is it possible to bypass it altogether and run the car normal?

Your cars computer needs the temp info from that sender as it goes off the temp (At idle) as to how much fuel to dump..FI cars use more fuel when cold to warm up (note the higher idle)..Also welcome to the forum.Have you cleaned your idle air control valve?

Welcome to the forum Adam.

welcome to the site

Thanks guys, glad to be here. I pulled the iac valve, the pintel was extended to the correct length and the gasket that goes around it seemed to be made of cardboard and not cut in a perfect circle, pointy edges jutting off. Would this affect the valve's performance at all?