Hi - I have a 2000 Toyota Corolla with the 1ZZFE engine with the timing chain. It has 135K miles on it and I need an expert. I am hearing occasional engine knock under moderate load but only after engine is warmed up. Sounds a lot like an EGR problem but I have not found anything that looks like an EGR valve on the engine. Did Toyota come up with some other way to do this? I have already replaced the catalytic converter as advised by mechanic but it did not improve the problem. Premium gas will suppress the knock but I am sure that is not the right answer.
I guess the correct term is preignition. Years ago, we corrected this kind of thing by adjusting the timing but today that is all computer controlled. I am now thinking it might be a problem with the knock sensor, either a bad unit or a bad wire. The Check engine light has not been on since the catalytic converter was replaced and the car passed the emissions test ok. The noise still says something is wrong that could cause major damage to the engine. It still could also be an EGR problem but I have not found anything on this engine that looks like a EGR valve or controller.