My 245 has dramatically failed the NOx part of my CA emissions test (which incidentally has become stricter in the last 2 years). I had a new cat installed a couple of years ago, but my mechanic says going without tune-ups probably caused the cat to wear out quickly.

1) is it true that this will ruin a cat?

2) It appears that there are quite a few makers of aftermarket cats out there. Anyone have any recommendations of quality brands to look for? I feel that if I just let my mechanic get one I am at his mercy again with respect to quality and also his probably generous markup.

3) It has been suggested that one cause of high NOx can be carbon build up in the cylinders. Anyone have recommendations for fuel additives to help burn these deposits out?

These questions are coming from the fact that I don't want to have to replace the cat again every two years. And I also don't want to be a GROSS POLLUTER!!

Thanks,

Groover

88 245 w/ 5 speed conversion, IPD sport exhaust, IPD sway bars, TME sport springs, Bilstein HD dampers, strut tower braces, poly bushings (rear),
Ernie Ball flame decals!