I have a 93 Lumina Euro 3.1 with rich smelling exahust created by runnig way too rich. Exahust is black in color and has an almost in between gas/vinegar odor. Low power seems like it is runing on two cylinders. Some more background engine has been locked up. However, compression is still seemingly fine acording to haynes manual 115-120 PSI on first comp stroke. After unseizing engine it ran fine for a few months delivering mail on a rural route (yikes!). Catalytic converter has been suspect and eliminated. Trouble Codes: 15: Colant Sensor low (Replaced) 23: IAT Sensor in this model (Replaced) 35: Idle Speed error replace IAC (Replaced) 43: Electronic Spark Control/Knock Sensor (Replaced) 53: EGR Valve (Not Replaced but cleaned and new gaskets noo longer Leaking)
Also new plugs, wires and coils.
Also two weeks ago i was cheking the ignition system control module with test in haynes manual and all cheks out. After doing that I cleaned up the spark pulgs again (they foul in about ten minuteswith carbon) I hooked everything up and started it and it ran fine for two hours thourgh various performance ranges. Next morning pull #2 Plug and it looked cleaner than when I put it in the night before, put it back and try to start and same problem starts again running rough and rich exhaust. Talked to some one who works at ford as a mechaninc and he said try the O2 sensor. I did and no change. I have tried to eliminate as many possibilites as I can but this seems to be and intermitant problem (our favorite kind) and like that friday evening if the stars are all alinged (which has nothing to do with it ) she runs. Any more suggestions.