Reader Question: I have a 1994 Chevrolet Cavalier 2.2L. I am having problem with the fuel system. I change the fuel pump, filter, air filter, PVC oil and spark plugs and wires. I cleaned the 02 sensor and throttle area.
The car will run but at a stop, it stalls. When I go to start it up it hesitates and then back fires.
Could it be the throttle sensor or the fuel pressure regulator?
At first thought, I would have thought you had a dirty throttle body and or idle control motor BUT those parts usually do not cause a backfire complaint. If the backfire is under the hood in the intake that means the engine is lean…too little fuel. If the backfire is out the tailpipe the engine is rich, too much fuel.
Putting a manual fuel pressure gauge on the engine when this happens is what you will probably need to do to determine if this is a lack of fuel problem. Check power and grounds to the fuel pump, relay, and computer.