1993 Isuzu Trooper 3.2 mileage: 97,000. My service engine light was always coming on but nothing appeared wrong with the vehicle. My gas pump and oxygen sensor had just been replaced, my oil changed and my charging system checked. My mechanic said that it appeared that I needed to replace my modulator but rigged it so it would work okay for a while. Will this hurt the vehicle? How important is this modulator?
Your car is equipped with a computer controlled engine management system. An independent auto service center can scan your computer for fault or error codes. The information should pinpoint the malfunctioning components. If a major tune-up has not been done recently, this could be the cause of your problem. Replace the spark plugs, plug wires, fuel and air filters, etc. Also, replace the oxygen sensor. In addition, service the fuel injection system. Clean the carbon deposits from the throttle bore and idle passages.