Well, I gave in and replaced the whole head pipe assembly to get rid of the P0420 and P0430 codes (catalyst efficiency below threshold on banks
1 and 2) I was getting (and the car was starting to sputter at stop lights). Now I get a different engine code - "P0402: EGR Flow Excessive". And the car still sputters at stop lights. Have I just exchanged one set of codes and 1 KilloDollars for a different set of codes? I also notice a tapping that seems to come from under the car when the car is accelerating to higher speeds (like entering a highway). The tapping speeds up and slows down with the RPM's of the engine.My car is a '96 Tbird with the 4.6L engine and 142k miles.
How screwed am I?
Thanks in advance for any help.