General Information
The backfire was only at higher rpms above 4000 when it was warm out. Now that it is colder the truck is hesitating on acceleration. Things i have done to the truck are a new magnaflow muffler a volant cold air intake with dry filter i had a diablosport predator tune on it and it does it with and without the tune. There is no check engine light on at all and when it backfires the check engine light does not flash or come on. I have had a smoke test done to check for exhaust leak and checked for a intake manifold leak and nothing. I have had 2 scans done at different shops and the specs came back perfect. Truck has a new tune up 2 months old i use 93 octane and vehicle is well maintained. The backfire started 2 years ago before the muffler was put on and yes i turned off the afm 4 years ago when i bought the truck. Any help or ideas.
