I start my car and it runs fine until it gets hot then it starts to lose some power and eventually when ive been driving for more than 10 minutes, if i give it some gas when its in very low rpms it make a gargling sound from the back, maybe muffler. It doesnt matter if im in gear or not. Only does it in low rpms. Do you think its just the muffler or some part of the exhaust. If so i dont really care cause im going to replace it, but it worries me that it might be the engine somehow. I just got a complete fuel system flush so i dont think its carbon build up.

 

doesnt anyone know what might be causing this noise.

 

I hear this too. Sounds like the muffler is farting. It happens at low rpm's when I gas it up an incline like this steep shopping center enterance near my house. I don't see any holes in my muffler but I did see very small bubbles form from a spot on the seem. All I can think is that the exhaust pressure builds up enough to leak through the seems in the muffler.?