Chuffing sound from my 300...?

[Dave26 0]

What do you guys think would be causing a chuffing sound to be coming from my 300, while under load? It sounds like an exhaust manifold gasket has let go but no black marks show, nor do I feel anything blowing out there. She's a '96 with 640,000 miles and has never been apart. Is a compression test and maybe a valve job in my immediate future?

[JerryB 10]

If there's no exhaust manifold leak it sounds more like a head gasket to me. Does it make a chirping noise when you take off from dead stopped??

[Dave26 0]

Nope, no chirping sound.

[Superdog 5,895]

broken clamp on a ATAAC hose?

[Dave26 0]

Broken clamp... I'll check that in the am. The sound is like a single cylinder blowing it's compression out somewhere and it sounds perfectly normal when you just rev it up when stopped. Under load she sounds like crap.

[fifth wheel 558]

Restriction in the air cleaner element.

FW

[Dave26 0]

The air filter was changed maybe 6 months ago and only has maybe 10,000 miles on it. But, I'll take a look.

[Dave26 0]

Problem solved. I had a buddy do a cold start while I stood at the engine. She puffed smoke out of the rear of the exhaust manifold for a few seconds and I could feel the hot exhaust with my hand. Now the fun begins!