In the last two days my engine has gotten extremely loud, it's only when I accelerate, hence I don't think it's a muffler problem. I've also noticed that it appears to be going through gas at an alarming rate (really helpful with $4 gas). Any ideas as to what this could be?

I would have thought its either going to be an induction or exhaust problem. My money is on the exhaust blowing but without hearing it I can only guess.

To clarify a bit, it's not a specific odd clunking or dinging noise, just that the engine roars whenever I accelerate - I mean a lot. Otherwise there's no rough idle and the car doesn't appear to be any louder than usual except when accelerating. And I somehow ran through 2-3 gallons of gas by traveling about 8 city miles.

I reckon its a pipe or more likely the exhaust split. So when you give it gas the engine rocks or the exhaust gas pressure causes a leak. That would tie up with extra fuel used as well. If the car was loosing performance then I would look for pipe leaking after the turbo compressor side.

Check the big turbo line where it connects to the "charge air cooler" (at the bottom of the radiator). I had a similar sounding problem when I replaced the engine on my s40 and didn't tighten the ~3" hose clamp on the bottom of the pipe enough. It's under the splash guard, so you'll never see it unless you take off the splash guard. I thought that it sounded like a table saw when it was leaking. Oops.

- Keith
2000 S40 154k (car), 127k (engine)