the car starts ,idels normal but no acceleration on 1998 Mercedes-Benz S320

the car is been parked for almost a year now it start and idels normal when i try to drive it no acceleration and i see no warrning coming on every thing seem normal what could be the cause

Asked by for the 1998 Mercedes-Benz S320
Where was the car parked? In a barn? Outdoors? Garage? A couple of other things to check...the gas may be in bad shape (old) and possibly gummed up the fuel system and you may have a blockage in the air filter housing- mice love to make homes in the air intakes and pack them full of debris.
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check the exhaust and make sure there is no blockage inside of it. the muffler or cat converter could have come apart on the inside and this would restrict the air flow and not allow the engine to breath properly. this woul keep it from accelerating.