I have a '91 chevy cavalair whose #2 & #3 coils are not firing. We’ve replaced the spark plugs and the firing coil but to no avail. Last thought may be replace the on board computer, your thoughts? Can’t quite go around driving on two cylinders so by chance your expertise will solve this mystery
What about the spark plug wires?
Relacing the whole car is the best option !
If you can’t do that then try a compresion test