We just changed spark plug wires (Delphi) and spark plugs. Cap and Rotor were changed less than 20K miles back and are looking good.
Old plugs (ACDelco) were good, with no strange *deposits/carbon build-up.*Unfortunately car is running even worse now - very rough idle with frequent intake backfires and spitting sounds on the exhaust. Mechanic believes it's an electrical issue more than anything else.
We have a Code 22 on the diagnose interface - TPS sensor low - just ordered the TPS and will post after we replace it.