I bought a used 1999 C230 Kompressor about 15 months ago, and bought the old line of "The wife just uses it for her long distance commute..." hook line and sinker. I'd found that outside the mandated service checks to maintain the warranty, the previous owner took very poor care of it.

Maintenance I've done (or had done):
I've had all the belts changed, had the brake system (but not the master cylinder) replaced, had the fuel filter changed out. Regular oil changes with full synthetic at the dealerships suggestion (but done by my own mechanic.)

I'm a DIY'er, but haven't found any guides online on how to do maintenance and repair to my car. (And chilton/haynes apparently thinks that if you drive a mercedes, you only do your work at the dealership)

So after the initial rough spots of taking over from the previous owner, getting things cleaned up/out etc... The car has run like a dream. Til this afternoon.

This morning it ran fine. No problems that I could recognize (not that this is a good indicator though)

I come home, car sits in the drive way for about 2 hours, and I hop in to run an errand, and the car at first feels sluggish.

By sluggish I mean that when I push the gas pedal, instead of getting the usual forward response, I get a pause, and more of a creep forward than the usual lurch. about 4 seconds later, it starts to pull forward.

It gets to about 30-35 miles an hour, and feels like it wants to shift to second, but does not. Even with the proverbial pedal to the metal I get little to no response.

First thought was "oh #$@%!, my transmission is going out."

Took the car to a nice straight-away.

Dropped auto-transmission into 1st, accelerated, shifted to 2nd smoothly, accelerated more, and into 3rd.

Figured it wasn't the transmission.

Took it home and popped the hood. Put it in "park" and listened to the engine. I pulled on the accelerator linkage, and the engine seems to rev up and then probably around 1500-1800 rpm (scientific wild assed guess) I'd hear a pop sound. But not a popcorn pop sound. more like a pressure releasing from a soda bottle kind of sound.

Engine seems to rev past it, and then lose power. It starts to rev up again and then lose power.

Any idea what could be causing this, and how to fix it?
Any clues?

Grateful for any help.

Its my only transportation, and I have a 30 mile commute on monday!

Thanks.

-MadManuel