86GL

I have a 86 GL and it suddenly wouldn't idle. Starts right up and I can rev it. It has a SPFI. When I put it in drive or turn on the vent or AC it wants to die quick. I can get it going and drive around but at red lights I have to keep my foot on the pedal. Anybody know a solution? throttle position sensor, maf, timing what can cause this. Adjusting the cable doesn't help. Thanks for any help.