my 90 zr1 ive done a complete tune up, is running better but now the pre-cat on the passenger side will glow red hot within a few minutes please some one please tell me where to look to fix this problem do i need to cut them out is it my cat, thanks Steve

 

Wow, do you feel exhaust at the left side tail pipe. Should feel the same as the right. If it feels very light I would suspect a blocked cat. So, yeah remove or replace the cat. Other than that, I have no idea. Hope this helps.

 

I bet it's running very rich.