Has anybody noticed any of the following after installing a Y-pipe?
-reduced fuel efficiency (not due to more spirited driving)
-more frequent engine knocking under load (running too lean?)
-more engine vibration at idle.

I know when I installed mine I didn't do a perfect job, one of the gaskets probably isn't seated properly causing a small leak, but would that be the cause of my problems? If I spend the $75 to have a shop profesionally reinstall it, will my above mentioned problems go away? If it makes a difference, I have the CA/NLEV emissions.

I'm also worried about how long a Stillen Y-pipe will last in Michigan and am contemplating just replacing it with a Cattman SS Y-pipe. I bought the Stillen Y used to begin with. Hopefully Cattman's fitment will be better since the Stillen Y needed some major "adjustments" to fit.

 

Did you reset your ECU?

 

No problems with my Stillen y-pipe. I actually got slightly better fuel economy. It might be the gaskets have it checked out at that shop when you have in reintalled

Maximadave

 

I haven't reset it yet. Just before I installed the Y-pipe I had my ECU reprogrammed at the dealer to fix a warranty issue (basically just an idle adjustment to fix a idle drop/stalling problem). Will resetting the ECU erase the new program?

 

Reset it by just unplugging the battery for a few hours or overnight... it won't affect any reprogramming done previously