My daughter owns a 1988 Bronco II that has taken to running poorly, but only intermittently. So, it makes for a tough diagnosis.
Symptoms are that you're cruising along smoothly when all of a sudden the engine starts running rough, and a strange smell is detected. A short time later it goes back to running smoothly, then the pattern repeats itself.
Can't find any loose plug wires, etc.
Any suggestions...other than selling the old crate? (It's served us well up to this point).