andrew29620

Hey guys. I have a huge problem with my 06 fx4. I got a k&n cold air intake installed about a year ago. Not too long after that my truck began to backfire and list power and heavy throttle. I cleaned my mass air flow sensor and it stopped. But about a week before I had cut my flowmaster muffler off and installed a turn down where the muffler was. Now the back firing is comin from the exhaust and there is a slight loss in power. I'm not sure if the problems are related but any help would be appreciated.

andrew29620

Any help would be appreciated.

csg85

Your getting backfire cause you dont have enough back pressure. No mufler=less backpressure. Im sure it only backfires when you have truck in park and rev it up and not when your driving.

andrew29620

I have a turn down for back pressure. It's like a bad backfire coming from the exhaust and it loses a lot of power and lurches. It didn't it before I cut the muffler off

bonez

CAI = more air flow
CAI + No muffler = even more air flow

Unless you have a tuner to add more fuel, your air/fuel ratio is probably off, causing backfires.

andrew29620

Any way to fix it other than buying a chip.

bonez

Put your muffler back on

andrew29620

It did it with the muffler on too

powerranger262

Any codes?

andrew29620

There's no check engine light but I haven't hooked it up to a computer. I can get a buddy to check it for codes tomorrow