Engine backpressure
 

Ok as yall know I got a 3.4 and I have been experienceing alot of backpressure I did a google search and found out its engine backpressure. Basically when I let off the gas peddel theres loud popping comming from the exhaust. Is this normal or is there a way to eliminate that sound it sounds horrible.

I have a cheap freeflow exhaust its a euromaster and im gonna upgrade to a flowmaster 40 series. All I know is its eating gas and sounds dumb

"A lot of backpressure" would mean your exhaust system has a restriction/ blockage. You've been reading in the wrong places if that's what you came away with. What you're hearing can be normal because a conventional exhaust system cancels out those sounds. Poorer gas mileage might be attributed to the fact your engine now makes a nifty vroom vroom sound, and you might be going heavier on the gas pedal to make sure others can "appreciate" the sound as well.

Well see theres the normal rumble then followed by real loud popping kind of like backfire i love the rumble but that popping is annoying almost embarasing being in a non v8 maro. From my understanding its unburnt gas due to lack of air and is finished burning in the exhaust system where the popping noise comes from . Ill see if i can find a video to show

That's afterfire coming out of the exhaust. Backfire comes out of the intake. Normally, the cat converter burns up any unburnt fuel. Does your cheap free flow exhaust also exclude the cat converter?

Could also be that the engine is misfiring which could account for the poor economy, and unburnt fuel in the exhaust.

From my understanding it has a cat not sure if its gutted or any good.

The car has no misfire

I wouldnt mind if it came from streight heads

If your engine is running properly there should be no exhaust pops, being that when the throttle is closed the PCM shuts off the injectors until the engine slows down to idle.
Unless the engine has mechanical problems (dead cylinder), raw fuel in the exhaust is not due to insufficient air, but because either too much fuel being injected or the fuel not being burned in the cylinder (misfire). The cat will burn the excess fuel, but overheat in the process, and eventually fall apart internally, This can lead to a clogged cat or more interestingly pieces of the cat get blown into the muffler and clog it.