I was thinking about installing my own straight pipes on my 1997 f-150 XL and i was wondering if i would run into any trouble during emissions testing?

 

It depends on how they test in your state. Here they plug into the OBD port and "ask" the truck's computer if everything is testing out OK. Also, they are supposed to do a visual inspection to see that all four cats are in place, but they rarely do if the OBD test passes.

If you delete the O2 sensors the check engine light will come on.

 

if you use your tuner to turn off the light will it still flag on the test?