I have a 2005 Chevy Duramax 4x4 C3500 and I was pulling my Stock trailer Saturday afternoon. I came to a stop sign and my transmission was in trailer mode. When I pulled away from my stop and started picking up speed, when my RPM went past 2,000 RPM my truck lost power and would not accelerate past 2,000 RPM. While in trailer mode the transmission wanted to shift at around 2,200 RPM, but the engine would not go past 2,000 RPM. I than switched my transmission to the regular driving mode and than the transmission would shift at a lower RPM and the transmission was able to keep shifting. Than I was able to get my speed up to 50 or 55 miles per hour and made it home. What would cause this problem? Help:

 

I would check to see if there are any codes showing.
If you don't have a reader, you can go to any auto store
and they will read them for you.

 

The check engine light has not come on. I think its a fuel issue. I did replace the fuel filter and this didn't help. I'm thinking it might be the pickup tube in the fuel tank.

 

Welcome, there is a ton of knowledge here on the forum.