I'm hearing an odd noise especially when I'm in D3 and decelerating. For example, just after 20mph, I can punch the gas a bit, and I'll hear this odd almost back-pressure bumbling noise. It's intermittent, and I can't hear while I accelerate usually; nor can I hear it when breaking. Only when immidiately after I let off the gas, or when I slowly accelerate...sorta like a rattle noise.

Could this be an exhaust leak? I couldn't find any holes in my exhaust system, and since I don't have someone to help me right now, I can't pin-point whether or not air is coming out near the gaskets.

This problem doesn't particularly hinder the function of the car, but it's just annoying. I have a GReddy exhaust (for about 5 years), so at idle it doesn't sound noticably louder.

The sound is a small snippet of like when you roll your tounge quickly...and then all of a sudden it goes away. I took it to a mechanic today (no charge) and he drove it....my luck....it didn't sound off when he was driving, though it was because he didn't know how to find the spot while driving.

Thanks.

 

A really, really long shot:
I'd check the routing of your exhaust system for any places it may rub / interfere with the body, look for polished surfaces, misalignment's or missing / damaged hangers. The exhaust can move from between accelerating and decelerating.....
Yeh, I know it's a guess. But it's kinda hard putting one's finger on stuff like this right off the bat

P