Can't get 2001 Corolla Check Engine light to stay off

My girlfriend’s 2001 Toyota Corolla has a recurrent Check Engine light problem. It has 144,000 miles on it. For the last few years, we have been unable to keep the light turned off. We have replaced the oxygen sensors and cleaned the MAF sensor. Our mechanic can’t find the problem. Every year, for Pennsylvania state inspection, we have to go through a rigamarole to get a waiver. We may not keep the car for much longer, but do you have any ideas?

Ted P.

What’s the diagnostic code that’s set?

Tester

Like tester said need to know the codes. If it is a p0171 cleaning the maf does not always work. If it is a p0171 see if you can get the fuel trim numbers, I have seen this code misdiagnosed multiple times.

If this vehicle is using oil (like most of them do) you will not get the light to stay off. The catalytic convertor is destroyed by the oil going through it. The piston skirts on these cars have too small oil drain back holes and the oil cokes up on the rings. Leading to a motor that goes through oil without looking like it is smoking. Not worth replacing a cat. And watch it die just like the first one.