Since we started getting these heat waves, my C240 has been ever so slightly having the engine shake and slightly hesitate like it wants to stall when giving it gas. Its mostly hardly noticeable but its there.

Anyone experiencing the same things? I use Ultra94 Sunoco gas.

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99 C43
98 S420
99 C230K
01 C240

The idle speed can be raised by about fifty RPM and the engine control module software can be updated to give the car a little more power. It's also possible that the high ambient temperature has placed a greater demand on the A/C. Remember, the A/C compressors on modern MB's provide variable output based on cooling requirements. With increased cooling demand the compressor is placing a much greater load on the engine, possibly causing the vibration.

So if thats the case...how do you fix it? My car does the same thing and it didn't do it before when it was newer. So something has to be worn. Any ideas???

The idle RPM and software updates are done using SDS. I don't know if independent shops can raise the idle with the equipment available in the aftermarket. I'm almost certain they can't do the software update. As far as worn parts, engine mounts would be a good place to start checking. I'd also look closely for any A/C or power steering lines that may be touching other components. This could definitely transmit noise/vibration throughout the vehicle. The belt tensioner should be checked as well. Good luck

I dont think its a vibration problem in my case.

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99 C43
98 S420
99 C230K
01 C240

I had almost the same problem. The engine vibrated at low RPM, idling at a stop, and when I took it out of drive this vibration stopped. It was a low vibration on the front end that did not affect the car, at least noticably, at any other time. At first I thought it was an engine mount, then something to do with the transmission, since it stopped when I took it out of drive.
I had a guy that worked on BMW's and other german cars, he had a small handheld computer he attached to a place under the dashboard (probably around the fuse box) and right away it gave him a code and also spelled out what the problem was, a misfiring #2 cyclinder.
I had thought it was a much bigger problem, but even without a diagnosis if I just replaced the coils (spark plug cables) and each spark plug (and perhaps even the distrubutor cap), it would have gone away. This is something you could probably do, or get any other mechanic to do that is not a $120/hr mercedes dealership. Even if this ends up not solving the problem it is still good (and preventive and inexpensive and could improve fuel economy) to do this. But in some cases, it will also solve the problem. Check it out. i would start with this since it is relatively simple and cheap.