My 87 coupe did the same thing. I changed out the dist and cap but that didn't help. I also bought a new throttle position sensor thinking it was getting stuck and still couldn't fix it. Finally my buddy pulled on the ground from the frame to the battery wire and it easily broke in half. My. ground and positive wire were both original. I contacted Latemodel Resto and ordered these wires. Problem fixed. I wish we would have thought about replacing the wires prior to replacing the dist, cap and TPS. Hope this helps.