87 GL-10 Idles Fast & Stumbles When Cold

[swarren]

Hello-

 

I have a 1987 GL-10 sedan- 1800/non-turbo/fuel injection (is this EA81 or EA82? I don't know the terminology). Lately it idles at about 2000 rpm when first started. If I try to drive, it will stumble and stall. If it is allowed to warm up for about 2 minutes before driving (enough to raise the temp gauge a couple of notches), the idle will drop below 1000 and it drives OK.

 

I thought that the air control valve might be the first thing to check. The valve gets about 12 volts with the ignition on and a cold engine, not running. The valve has a resistance of about 10 ohms and no shorts to the body of the valve.

 

After the car is warmed up for about 5 minutes, it idles smoothly at about 900 rpm. Pulling the connector from the air control valve reduces the idle to about 600 rpm and rough- so the valve seems to be doing something.

 

Can I do anything to try to clean or adjust the air control valve? It looks like a candidate for a shot of carb cleaner spray but I don't want to wreck anything. Or should I stay away from it and look for other problems?

 

Possibly unrelated problems: After driving the car for a few minutes and above about 2500 rpm, the check engine light comes on. It has been doing this for a long time (before the idling problem started) with no effect on performance. I've thought it might be EGR or oxygen sensor related but have never checked it out. I have also had an intermittent overheating problem.

 

Thanks,

 

Steve W.