i have an 06 duramax gmc 2500 truck, the engine light came on saturday. truck ran fine but sounded loud (diesel sound) when idling and was sluggish when engine was cold. dropped it off at dealer they called back and said i have water in the fuel. the thing that gets me is i have used around 10 gallons of fuel that i put in when i filled up a week before this happened. would it take this long for the water to show up? has anyone had this happen and gas station or their fuel supplier pay the repair bill? i'm not sure if truck has a "water in fuel" light i don't have it back yet, if so i wonder why it didn't come on sooner.