I just removed my resonator and muffs off my 94' Cougar 4.6L. And I was driving it for a while with no probs then i got my "Check Engine" light on. I about crapped my pants. What is the deal? I didn't remove my Cats. So it can't be the O2 Sensors detecting that. It may be something else. I also had a cold air intake installed. But i know i set that up right. Besides that everything else is stock. Help Pleeeze!!