The engine service light came on after about1/4 tank from my last fillup. Figured it might be fuel the engine didn't like (I had a car like that). Went to another name brand station a day or two later and filled tank. Shortly after engine service light went off. Ran tank down to about 1/2 maybe a little more. Engine light came on. Went to another name brand and filled up. Engine light went off shortly after. Going to work this morning and at about 1/2 a tank engine light has come back on.

Any ideas? I'm probably stopping on the way home at an auto parts store and see if they will hook it up and check the service code

Sometimes they come on when the gas cap is not tight enough.

How many miles are on the truck?

I have an 07 also. You check your fuel filter? Does your 07 have the info buttons on the stearing wheel?

I wonder is you're losing fuel line pressure from a clogged filter or faulty pump once the fuel level drops below 1/2 a tank? I'm not a diesel mech. but I do know that this is sometimes a problem on gas vehicles with the pump in the tank.

Did you get the code read?

I went by and the error code was for EGR malfunction. And yes the truck does have info buttons on the steering wheel.
dtp807

The EGR is one of the only issues you are going to have out of that truck, that and injectors.
I hate to tell you, but changing fuel isn't going to fix your problem. I'ts time to go see a Dr.

No pump in the duramax tanks

No injector problems on the '07's, they figured that one out after the first gen.

Had same problem after 5 trips to shop they found the pump and egr were bad and also a water leak in the line to the egr. They replaced the complete egr system and all conecting lines and foun another one with a leak. Don't know what all they found for sure. They said all this was on the firewall and it still took them 2 days the last time it was in there. Have now driven the truck over 3K miles since they did the replacment. This was all covered under the 100K warrenty. I have the 2007 classic.