Just wondering what mods will make you fail the emissions test. You guys replace your Y-pipe, cats, intakes. Some people here pass, some fail. I am in Maryland. Whats the truth behind that? Or you have to return to stock everytime before the test?

 

Just about the only mod that you can possibly fail emissions with is a y-pipe. But like most ppl here have done before an inspection, they warm up the car and take it for a spin 15min before the inspection. All is well after that...

 

Yeah if the car is running warm you should be fine. And when at the insepection station leave it running so it does not go cold again.

SuDZ

 

and u have to have a functioning cat..not like my all punched-out cat...

 

You just need to live in a state like Michigan where you don't have any sort of inspections or emission tests.

Stereodude