Check engine light
 

Will an off-road H-pipe trigger the check engine light on a 91 5.0? If it does, what can and should be done to prevent it from coming on?

Did you use your old O2 sensors? What did they look like? Do you still have the smog pump hooked up?

no, only on the 94-current mustangs will the check engine light come on, (the use of mil eliminators fixes that) but it won't come on on your 91.

Well, I have the pipe, its just not on my car yet. I was just curius because I've heard it will trigger the check engine light with no cats or something like that.