2003 Duramax 6.6.

[jimwd]

My 6.6 just started smoking some when idling. Does not use oil between changes of 3500 to 4000 miles. Water in fuel light keeps blinking. Have changed fuel filter several times but light keeps flashing water in fuel. Have opened the cockvalve in bottom and drained several times also. Truck has not lost any power what so ever. Could the light water in fuel light flashing have any thing to do with the smoking.

[Mark Rinker]

Probably unrelated. See other treads in this forum for troubleshooting your WIF indicator.

The smoke at idle is almost always an early indicator of injector problems. Try treating your next 3 tankfuls of fuel 'heavily' with a good diesel fuel conditioner.

If it doesn't clear up, it will probably progress to the point where you will start having driveability problems, unusual diesel rattle, etc. Your oil level may also start increasing as unburned fuel enters the crankcase.

If the condition persists, get to a good dealer and have the injector return rates tested. If you are still inside warranty (I believe its 200K for 2003 trucks?), you should receive all 8 new injectors. Search and read other related threads on this forum, make sure you get all 8 as that is what you have coming...