My engine light came on two years ago and I took it to Auto Zone to get tested. I was told a small emission leak and not to worry to much about getting it fixed cause it wouldn't hurt anything but, my engine light would stay on. Since then I have replaced the fuel pump twice, of course I bought the "used ones". Then I started noticing every time I stopped to get gas my car was turning over but hesitated to start. I took it back to Auto Zone and they hooked it up and said large emission leak and multiple misfires. The entire time my car run great. Three days later my car started idling real rough and sputtering. Engine light flashing and you could hold gas pedal to the floor and it would barely go. I parked it immediately. I replaced my fuel cap, plugs, wire set, ignition coil, oil filter/ oil. Still the same.
What do I do next my car is idling rough and engine light flashing? on 2004 Chevrolet Cavalier
What you need to do now is what you should have been dong all along and that is have a technician diagnose and attend to the problems correctly. Not fixing it completely and not using quality components makes it more difficult to diagnose what's wrong. In a lot of cases like this not only is the original failure still there, additional problems often get added on top of it either by the installation of questionable components or just because more things have been breaking and/or wearing out on the car. The biggest problem right now is that misfires ruin catalytic convertors, and there is no way to know from here without doing real testing if that is yet another part of the problem now or not.
take it to a mech and seek diag and est. most likely misfires are causing light to flash indicating poss catt damage may occur if not repaired