Ok, new to the forum. Ive run myself into a corner not knowing what to think about this. First off there are NO CODES. Except the evap purge solenoid. When driving it constantly feels like the truck has low power. In overdrive, pulling a hill and it feels like someone threw a boat anchor out the back. Truck slows way down while im gradually pushing on the gas. Feels like fuel IMO. Studders and slows way down until finally it downshifts and gets its butt up and moving again. Now. . .things i done or tried.
1. New fuel pump assembly
2. New plugs, wires and coils
3. Gutted cats
4. 02 sensor(cause it had a code for bank 2 sensor 2)
5. Cleaned throttle body and maf
6. Removed and cleaned injectors and rails
7. Double checked fpsi 60psi across the board even during hesitation
8. Checked compression all above 160psi
9. Sprayed brake clean all around intake(no change)
10. Cleaned ground on drivers side frame
11. Checked continuity in coil harnesses.(changed harnesses) no change
12. Swapped new coils with a friends good ones just to see(no change)
I am at my witts end!

 

Make, Model, engine, miles, length of ownership...

 

If we knew what you Hummer you were asking about, we might be able to help.

 

almost a year, drove great until fuel pump went out. Then i did it and the tuneup at the same time. Its just been getting worse. 04 hummer h2. 160k

 

I see you posted this over in the correct H2 Section. Hopefully people will help out over there.