My '87 5 spd just started acting up at idle. At 1100 rpm it runs smooth. I have to keepmy foot on the accelerator pedal however. Below 1200  the engine surges, slows, and dies. Gas is ok, maybe a vacuum leak, MAF or controller issue? It has been running perfectly til this....

swap the air filter. Problem solved! The car does need quite some air and a clogged airfilter causes this problem. Try putting the airfilter directly on the MAF without the housing, and witness the effect on the engine: it won's run (or almost not). Take the airfilter off and she breathes again ;-)