I keep getting a P0170 Code on a Check Engine Light/Engine Electronics ... I looked up the code and it says, "Fuel Trim Malfunction (Bank 1). I don't have the foggiest idea what this means? If you have any clues ... I sure would appreciate your help.

Some background: Car is a 1996 E320 (gasoline 6 cylinder). Mileage is 57,500 miles. All maintenance up to date.

Thanks for your help!