Just an FIY I bought a 2002 monte, and about a month ago noticed it didnt seem as fast as it should be, and when help to the floor, it would hit redline, and not shift up. Well it kept getting worse and would do this no upshift bit at
4500 rpm. then the CEL would flash, let off the gas and the CEL would stop flashing. I poped in a new air filter, same deal, and some fuel injector cleaner. I tried a few more times to floor it, and it got to 4500, and back fired! then the CEL stayed on, so I took it to a dealer, and they replaced the CAT free of charge, and it runs like new agian. Wierd...