Please help! 1998 sl 500 was stored all winter. Started intermintently but not regular enough I guess. Charge battery and start. RUNS ROUGH..chugs like a train..low level boom ..sounds like a quiet but deep drum and seems to want to backfire. NO throttle response at all from the gas pedal. Could a computer have fried when I hooked up the battery again? Water in gas ? I used stabilizer before storage...in an insulated but not really heated garage. Suggestions PLEASE..

 

Two things come to mind. You might have corrosion built up on electrical connections. Get some electrical cleaner spray from an auto supply house and clean the electrical contacts on all the plugs in the engine compartment.

The other thing is wiring damage. Stored cars can be accessed by rats and other small mammals that love the taste of german insulation. Look your wires over good and see if any are chewed through.

I have run into both at one time or another.

Sam