I have an 87 TA 305 TPI. I have a miss at idle that is very confusing. The car will idle fine but every couple minutes it will have a quick stumble in the idle, it is just enough where you can feel that it stumbled. I have had the pickup coil replaced ( AC Delco) & had the module checked at autozone (the old one Accel went bad replaced with original Ac Delco unit). I have also replaced the dist. cap & rotor with new msd & the wires are new taylor wires. The plugs are new Ac Delco. Are there any usual causes for this symtom?

 

dirty IAC?

 

As in the engine misses 1 single event or actually coughs through 3-5 strokes?

A tiny exhaust, or maybe even a tinier intake leak may cause something of this nature.

If it only misses one event every couple minutes, I don't see any real problem. The universe is not a perfect place. An extended symptom may indicate something is wrong, and I think the leaks would be a good place to start.

 

Could it maybe be a small vacuum leak? Isn't there a way to check for these with a propane torch(benzomatic)? Does anyone know how?