I'm starting to get freaking pissed. I had a Cattman y-pipe installed the other day to hopefully get rid of my P0420 code. I've had it on for about 100 miles and it's making a weird sound when I accelerate past 2k rpm, sort of like a faint chirping sound. Now I just pulled 3 error codes today, a P1126 for a thermostat, and a P0158/159 for an O2 sensor.

I'm not sure why I'm now getting the code for the thermostat and how that's related to the y-pipe. The stock heat shields weren't put back on. I wonder if that affects things.

As far as the code for the 02 sensors, I wonder if the original P0420 (catalyst) code was just masking the P0158/P0159 codes for a bad sensor. I think I'm going to put the original pre-cat back on, clear the codes and hope for the best.

Any ideas what might be going on?

 

theres a poll right now up about how some people have had 02 sensors crap out as soon as they get a new y pipe.. its common....but why not look into some o2 simulators..and idk about the thermostat. sorry