I haven't gotten an answer hoping this was something else, so I'm kind of thinking that the ECM or prom may be shot. Sometimes when I'm driving the SES light flickers. When it stays on it runs bad. If I smack the dash by the computer the light turns off and it runs better... until I stop then it either stalls or idles really low. It won't pull up any codes, it acts like nothing happened. Also when the light does stay on the fan turns on with the light. I'm sorry if it's not enough information. If anyone needs anymore I'll try my best to put it down.

1986 Trans Am 5.0 TPI stock for now

 

My first thoughts lead towards poor connections or bad wiring. Check for tight, clean connections. Look for chafed or torn wires. Check and clean grounds. It may get tedious, but do it anyway.
It sounds intermitent and I would guess a wiring or electrical problem. Good luck. If you have anymore info that you think is useful, put it up.

 

Try another ecm if it's a 1227165, they've been known to do things like that. 2nd guess is the MAF.

Maybe Need4speed has an answer with better information.

 

The ECM number was 1227165. When putting another ECM into the car does it matter which one you put in? As long as it has the original prom?