1991 Isuzu Stylus • 4 cylinder FWD Manual • 255,043 miles

I was driving down the hight way no problems with it then the car starts******** then my check engin light comes on the idle changes or it just****** at what ever speed I go I replaced alltinator fuel filter cap rotor spark plugs a wires but it went to the coast and back with no problem and when it****** I get bad mph what does this mean
Jonboy 123
April 14, 2011.

Could be caused by one of the following below

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note: If it doesn't apply disregard it and keep testing.

Apr 16, 2011.