shotgun backfire

**lovedrvr** · 06-19-2009, 04:14 AM

well this scared the crap out of me.
done working this morning,had some stuff to do sat there idleing for about 10 min,pulled out the parking lot ran it through 1,2,3,4 at a min throttle pace for about 1/4 mile,got up on the big road had 2 trucks getting on in front of me so i slammed it to the floor at top of ramp to get around them ran up to 90 mph got around and moved back over,then i let off the gas compleatly to drop back down to 75 when BOOM sounded like a shotgun went off under the car i even felt it through the center armrest. (WTF)have never had it do this before, ANY IDEAS ????????

car still runs great did not happen again (yes i did a couple of repeats)

car does have the slight popping on decel

has no cats,and flowmaster

i have a ory and think i will have the 2 slip joints welded (will this help with the popping,and could this have anything to do with the shotgun backfire)

ANYBODY HAVE ANY IDEAS ??????????? that can't be good on things,i felt the shockwave very strong.

i would like to fix the problem now if there is 1.

**Cutlass** · 06-19-2009, 07:22 AM

Usually it because there is too much unburned fuel in the exhaust and it explodes. Check your muffler, it maybe be ballooned out from the explosion

**VENOMOUS** · 06-19-2009, 07:41 AM

Exactly what he said. When you lifted their was still unburned gas and it ignited by the heat of the cats or just higher than normal exhaust temps. We used to take our old cars and trucks back in the day, before goingto the muffler shop and getting a new muffler, and rev the engine then shut the key off, then turn the key back on with the pedal floored and BAAAAMM! Shotgun and it would blow the seams of the muffler. The muffler guys would always be like WTF?

**lovedrvr** · 06-20-2009, 03:46 AM

ok great
i checked my LTFT and it was at -4 so i changed it to -1 still runs great.
ill check the exhaust today.i am going to put no leak band clamps on the 2 slip joints

**JoshieDoom** · 06-20-2009, 03:50 AM

Mine does it just about everytime I accelerate then left off fastly.

Ive had some people thing im backfiring but its technically not backfiring.

Put it in a lower gear (35mph at about 3krpms) and let if wind out, then let it slow down and tap the gas real quick just enough to blip the throttle Mine always is the loudest then.

**lovedrvr** · 06-20-2009, 11:10 PM

i have just switched from 2.73 to 3.42
also i have noticed ever since the sonic boom on decel now it just gurgles a tad,before it popped a tad no more popping.
i think it may have had a leak in the ory slip joint and it was cold that morning,but anyway no damage and sounds better,must have sealed up the leak with the boom.