Okay Ecotec nerds. Need some help.

My '06 2.4 (Has the 5 speed) has a little bit of an issue.

Occasionally my car will eminate this musty, acidic smell during acceleration and sometimes during sustained highway RPM (2500-3000.) I think it's experiencing blowby as well (Soot in the exhaust tip.)

The car only has 80k on it, so I'm hoping I haven't got fried rings or anything...Anyone have any idea on what's going on, or how I can stop what I assume is blowby?

 

During acceleration, I was gonna suggest slight clutch slippage. Just enough to slip and get that burnt clutch smell.
BUT. You say it's also at sustained highway speeds. Hmmm. Have someone ride behind you both during acceleration and constant speeds. Let them observe if you've got any smoke from the tailpipe. Blowby? You would probably notice that smoke more between gears when you shift.
3rd choice. Failing catalytic convertor?

 

Or perhaps a leaking flex pipe at the exhaust manifold?

A thin coating of soot inside the end of the tail pipe is pretty normal these days.

 

I can't say it's the clutch. (Definitely know what that smells like since I ground the hell out of it once when I first got the car.)

I can say for sure that the car doesn't smoke. I've had friends behind me confirming that. Starting to get slightly worried now...

 

Cabin air filter? Although it may not have anything to do with acceleration, It will smell funky when it needs changing

 

After 7-8 years, I wouldn't be surprised if it needs changing. Should probably do that anyway.

 

Converter? Do you know what that smells like, so you can eliminate it?

Lots of times when I'm behind small displacement engine cars and they push down the man pedal, I can smell their converter clearing out

 

I'm thinking ac pipes may have things growing in there.

I wish they had smell o vision to help sort this one.

 

I'm guessing exhaust leak at some point, probably flex starting. I had a bad muffler gasket at 80K, though.

 

Oh god, don't tell me that! I don't want to have to screw around with the exhaust. (I also know that if this is the case, I'll end up putting on a full Flowmaster system) I tend to upgrade once something is shot :P