HI GUYS! Need a little help here. I got a 2003 c240 with engine misfires on cyl 4,5,6. It also has a crunch sound when I start it up and a grinding noise at times when I accelerate or turn to the left.

Pertaining to the misfires, I already changed all spark plugs to the OEM plugs. Checked the coils, switched them around to see if the coils were the problem but the cylinders did not change so I knew it wasnt that. I cleaned the MAF sensor and it rode good when I test drove it but the next day, I was driving up a slight hill, had to push on the gas harder and it misfired again with the engine light flashing. Got the same codes for misfire in cyl 4 5 6. At a loss on what to do, I thought it couldve been a vacuum leak but I fixed that and still nothing. Any ideas? Please let me know.

 

Sounds like injectors. I had similar issue. Two were misfiring. So I changed them all. But be prepared, if you have a lot of misfiring and you go with that for a long period of time, you will soon have another issue with your catalyst converter.
Visit a repair shop and be prepared to change all the injectors as soon as possible. You dont want to have your car completely stopped few hundreds miles away from your home. Towing will cost another few hundreds if you don`t have Mercedes Mobilo service or any kind of reliable road side assistance.