smog pump delete 91 mercury

Replace the smog pump. Yes you need it. The computer monitors the smog pump and without it on the vehicle your check engine light will come on and stay on. You'll never pass inspection that way. Hope that helps! Jim

I had a much older Nissan pickup (about 1980) that I disconnected the smog pump. I must have gained 50hp (no kidding). That pickup ran like a hot Z car without the pump. I doubt it would work on your car and you do need it to pass inspection.