Stubbling and Chugging

[TO THE MAX]

Just this week my 6.6 started chugging when I stepped on it to go into passing gear. It started stubbling and speed fell until I let off the pedal. When I just barely step on the gas it would come back up to speed slowly but wouldn't go above 65 mph. Went that way until I could stop and shut the engine off. Waited about 3 minutes and restarted it. Ran fine and went back to normal until later in the week. Repeated the same situation. It doesn't create any smoke just stumbles when I step on it for passing gear and not all of the time. Almost feels like flooding out with a carb. It's been a while since fuel filter has been replaced so I was going to start there. Any help would be appreciated.

[madmatt]

your on the right path by starting w/ the filter.

[leolkfrm]

I would put additive such as power service in the tank to help clean it up

[hapaschold]

imo, fuel filters every 10k.....i do every other oil change.....while oil is draining.

not knowing your location, you might have gelled up or perhaps if this happened after a refuel, a bad load of diesel.

my 02 dmax gelled up twice, but so far my 06 dmax has made it thru the last 2 no problems. maybe a design change on fuel cooler ?

[Mark Rinker]

What year is your truck? LB7? From your description of the 'stumble' I'd suspect you have frozen filter from water absorbed now becoming a solid, restricting flow.

Changing filter should do the trick.

[Dmaxwrench]

You have air entering the system.

Dale

[Mark Rinker]

You have air entering the system.

Dale

Welcome aboard! Are you a GM certified mechanic? By your name, it looks like you might be...

I've had many LB7 trucks do what is described here, requiring only a filter replacement to correct. What brings you to the conclusion of air entering the system? Would it make sense to change the filter first to see if it clears up the problem, before digging deeper into the fuel system?