Fluttering noise under car

[bandit71]

Trying to figure out a noise coming from under my 2004 Jeep GC. When accelerating, I can hear a fluttering type noise coming from directly under the car. Noise goes away when not accelerating. It is louder on the highway. My guess would be some kind of exhaust leak but not sure. Could the transfer case make any fluttering noise on acceleration? I just changed the transmission fluid and having no known issues there. The noise only happens when it is moving and pushing on the gas pedal so I cannot get under the car and isolate it. I cannot replicate the sound by pushing on the gas while in park. Anyone ever run into this?


Thanks

 

[Poop3000]

happens only under load. likely an exhaust leak. check your exhaust manifold at the collector (where all the exhaust pipes from the different cylinders come together). likely cracked there. don't bother replacing it with another factory manifold, go ahead and buy an aftermarket header. MUCH stronger, and more power for your jeep.

to prevent this problem from recurring, be sure to check motor mounts and be sure all of your exhaust hangers/stabilizers are holding effectively. ESPECIALLY the one on the transmission. seems to be a weak spot.

easy way to check those motor mounts is a two person job. one person watches your engine with the hood up while the other person depresses the brake (HARD!) and steps on the gas while in gear. a torn up motor mount can be hard to spot until your engine looks like it wants to leap out of the engine bay.

good luck!

 

[bandit71]

Thanks! I'll get under there and try to find some cracks or leaks.

 

[W00GYB00GY]

It could possibly be your catalytic converter...

 

[Poop3000]

good call, that one totally slipped me. that one can be easy to hard to diagnose, depending on just what stage it's in. sometimes your check engine light will help you out, often it won't.