I have an '02 protege 5 with the 2.0 liter. It has 157000miles on it. It developed a knock in the engine which sounds like its in the top of the motor. I changed the timing belt and water pump thinking it was time for the belt to be replaced, and now the knocking only takes place above 2500 rpm. The check engine light is on and it was for the #2 O2 sensor(behind the catalitic converter low) i bleive it was a PO402 or something. any idea if this is a timing issue due to the low O2 sensor or if i may have a bad engine? any help is appreciated.

thanks,
Jeromie

 

Not that it matters, but it is a manual transmission and does this reguardless of in gear or out of gear.

 

is it a random noise or does it has a pattern? i dont think that sensor affects the timing of the car. adjustments made by the computer use the signal coming from the upstream sensor. if possible, let us know the correct code. p0402 is egr related and problems with the egr valve are very common in the protege. but it is better to be sure of what code you have so you can concentrate in the problem area.