My 2002 C240 with 140,000miles started to have a rough idle, while in drive, at low RPMs. It feels like the car is going to stall but never does. No CEL on.
I had a tune up about 18months ago with all coil packs, plugs and wires changed. Recently took to a garage that specializes in MB and had Harness wires changed, engine diagnostic done, engine mounts were OK with no fix. I was give injector cleaner to add to my next fillup to see if that corrects the problem.

Any other suggestions? Garage recommends a compression test to check the engine, if everything checks out good then move to bench test the injectors.

thanks!