Q: My daughter’s 2002 Chevy Malibu six cylinder car engine light stays on constantly even after replacing two catalytic converters. We have had it analyzed on a diagnostic computer and the computer keeps telling us that the problem is with the catalytic converter. What can you tell her to do to solve this problem? Is this a problem with this particular make and model of this car? It is getting pretty expensive to keep replacing converters without solving the light coming on. Any help or suggestions would be greatly appreciated!
A: Your Chevy Malibu is no better or worse than most other cars out there from that age. The fact that you have replaced the catalytic converter twice actually gives us something to work with. First of all, are you using a factory part or an aftermarket replacement catalytic converter? If you are using an aftermarket unit, you need to know that all aftermarket cat cons are not created equal. There are various qualities, just like all other parts that are available for purchase. If you are using a factory part, the next step is to find out why it keeps failing. A few common failures that can cause cat con failures are leaking fuel injector/injectors, leaking fuel pressure regulator, vacuum leaks in the engine, or a sensor giving the computer wrong information, which will cause an erroneous mixture of fuel, air, and engine timing. If your technician is not trained to diagnose the problem, there are many out there who specialize in just this kind of problem. Just a heads up; looking at the long term and short term fuel trim numbers is an excellent place to start your diagnostics.
Q: I own an ‘87 Nissan Sentra. Car runs great at first then after warming up it starts to chug and lose power, sometimes almost stalling. I did a complete tune up — no luck. One mechanic says it’s the ignition module and one says fuel pump.