[duffyatkinson]

Originally Posted by Mike McKinney

Great thread, I'll give you guys a quick description of what I've dealt with for years. When I bought my truck I had the guys at SOS Performance in Panama City, FL install a custom exhaust. They went with TRD headers, Borla cat-back, and Magnaflow cats. They said from their research that this gave the best performance. Since then I've had constant issues with MILs, most notably, 420/430 codes, which are now constant. They never could figure out the problem, nor could two other exhaust places I took it to, it boils down to the fact that the Magnaflow cats are too high-flow for the Toyota ECU.

I've constantly monitored the engine for years now with no undue problems that I can tell. I changed one of the rear sensors to no avail. I purchased a set of MIL eliminators but haven't installed them, hoping to find a better fix. I even called Magnaflow and spoke with one of their techs but he was stumped also.

I've done a ton of research but unfortunately haven't found a solution except for to replace the cats and go back to factory ones, not wanting to for cost reasons. Anybody have any input to my dilemma? I think in about six months I'm gonna have to do something since I'm in a different area now that requires emissions testing. Any help would be appreciated.

A couple of questions.

Q: Are you sure the MF cats are correct for your truck, and if so, are you sure that they're failing?

Q: How did you determine that it is a "flow" issue with the cats?

Q: Have the rear sensors been swapped out to see if they're reading right?

Q: And, are you sure that you don't have any type of exhaust leak between the headers and the cats?