My 85 SE has the same problem, it sputters at low rpm randomly when the engine heats up. Coolant temp is up more than usual. I can feel the secondarys engange like normal. I recently replaced the cap and rotor for the distributor, put in some new plugs, and checked all the ignition wires. The problem does not seem to be electrical. Any one have any suggestions as to what is making making run this way? My only other ideas are that it is is something wrong with the fuel pump or acv valve (because it randomly stumbles around 2500rpm). I also put some techron in it and it runs a bit better but car still sluggish.

 

try changing the fuel filter and check the timing

 

I'll go pick up a fuel filter tomorrow and see what happens. Even if that's not the culprit it's a cheap part that needs to be replaced anyhow car has 165k on it and since I've owned it hasn't been replaced. What's the easiest way to check the timing?

 

Timing light. The 85 FSM can be downloaded from the FAQ sticky at the tp of the forum.

 

Do you have a carburated 12A in it? If you do, I have the same problems with mine. I have a 1980, and it sputters at around 2500 RPM and you can feel it even driving the car at speeds around that RPM range. I have done everything you have done, and still seem to have the same issue. Let me know if you discover a solution to this problem.