2002 Mercedes Benz S500

Engine Performance problem
2002 Mercedes Benz S500 V8 Two Wheel Drive Automatic 68000 miles

My car took some water damage to the right side rear and front floor boards. This shorted out some computer and electric components which were replaced. Since I picked it up after having the new computer put in it, I have noticed the gas mileage is terrible. This morning on my way to work, about 11 miles, 10.5 is highway driving, my gas mileage was 8.2 mpg. I could see the gas gauge moving. Does this car's computer affect the fuel efficiency of the vehicle? What do you think is causing such poor gas mileage. I always use super unleaded.

Your thoughts are really appreciated.

Have a great day.

Mark Rodriguez
February 3, 2009.

Absolutely the vehicle computers will affect fuel efficiency. Keep in mind also that when a car takes on water corrosion can begin to fill electrical connectors causing high resistence which can cause strange issues in vehicles. Do you currently have any warnings on in the dash? Are there any drivability issues other than MPG that you are noticing? Hesitation? Poor throttle response? Sluggish performance?

Mar 16, 2009.
Also how did the damage occur? Was the car in a flood or did a 5 gallon bucket of water dump in the car? How extensive was the damage?

Mar 16, 2009.