Hi I have mercedes c 300 drive not smooth as before pick up is also not same some time
I would say the mechanic had did something to change the engines performance during his tune up , sometimes if they aren't careful they knock of f wires or dont tighten screws or connectors very well when in a rush to destroy the next car in line. Once in a muffler shop if I hadn't been there the mechanic hung a lit torch over the rear axle and almost put my gas tank on fire while he was on the phone real smart guy eh .
You don't say how many miles are on the car, but maybe it's time for a complete tune-up on the car, this will included plugs, wires , fuel filter, cleaning the injectors, air filter, changing the oil as well as the tranny fluid !
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