Duramax fuel injector cleaning DIY
 

I've recently done a DIY fuel injector cleaning on the Duramax and figured I would share the instructions in case anyone is interested. GM has their own particular fuel injector cleaner that they say to use, but it's crazy expensive and I'm cheap, which is why I do it myself in the first place.
I've read a few reviews on the Seafoam diesel treatment, where you fill your fuel filter with Seafoam and run the truck. To me, the Seafoam would get diluted pretty quickly and any cleaning would have to happen in a very short amount of time. I took the GM directions and used my own combination of cleaners mixed with some diesel.
First, take your 2 fuel hoses loose on the driver side of the engine. They're the push lock type fittings and you need a fuel line tool to release them. Now clamp a few feet of 1/2" hose to the bigger hard line and 3/8" hose to the smaller one. Run both lines into your bucket of cleaner. The smaller one is the return so it doesn't need to be submerged. The 1/2" hose is your new pickup and needs to be in the bottom so it doesn't suck air.
Add your cleaning solution and crank the truck up. Let it run until you're low on cleaner and then either add more solution or reattach your fuel lines. It will run for a surprisingly long time. These engines don't use much fuel at idle.
That's it, it's pretty stupid simple and I'm happy with the results.