GTOsRamairSilverado

Ok this is what i got ............about 4 days ago my truck started making a puffing sound. It almost sounds like it is backfiring. the truck is pretty much stock. It has no cats, only has a bullet, and it is wheatley tuned. the truck only makes this "puff puff puff" sound when i give it gas to pass up a car. If i have the truck in neutral or park and rev the engine it doesnt make this sound. what could it be??? misfire? not enough back pressure?

Bowtie70SS

iTrader: (10)

If it is backfiring thru the intake it could actually be detonation from bad gas or you are running too low of octane. The reason it dosen't do it in neutral or park is that there is no load on the engine when you are free reving it. I think you need to find a way to data log it or some way to see if it is pulling timing due to knock retard. Does it ever ping (people also call it valve rattle)?

Dave

GTOsRamairSilverado

the truck use to ping a little bit before i got it tuned. since the tune, i havent heard it ping anymore. imma try i higher octace gas or buy an octane booster tomorrow to see what it does

AintNoHo

Sounds like an exhaust leak to me. Look for spooge around all the connections and retighten the bolts.

GTOsRamairSilverado

ok will check tomorrow thanks !!, but if it was a leak wouldnt it do it when it is in neutral and in park also ?