noobie

Thanks for all the input folks. I never mentioned a tune being on the truck, because I thought there wasn't one on it... turns out the was a parameter set up to manage the fuel pedals response. Truck has been working fine since this was noticed. It's a bitter sweet thing.

Yes it does. But, not for very long.

New plugs took the stumble and stalling away but, there is still a lack of power.

Checked fuel pressure. When hitting the key just to prime it, I got 40lbs. I let it set for about 20 minutes and it stayed there. While running, it was just above 50. My gauge didn't have a dump valve on it to try that exact method. And of course the thing didn't even stumble when I had the gauge on it. Before I pull the bed and tackle the pump I may try this with a different gauge. In the mean time I figured I would check plugs... two were loose. They're original to my knowledge I'm changing them regardless being there's just under 160,000 on the truck.

Removing the upstream sensors did not do the trick. Man did it sound like a demo car though.

Well, being I just replaced them, they shouldn't be that hard to remove.. other than the placement of them of course... I'll get back to on this.... Thanks (fist bump)

Would you still think that if I told you while driving and I put it in neutral, shut it off and start it back up... put it in gear and get on the pedal it accelerates fine and dandy? Then let off the pedal, get back on it and then the lack of power/acceleration issue is right back? Yes... I know I left that out in my initial post... whooops!

The truck is a 2006 GMC 1500 Denali with a 6.0.... It had codes for upstream o2 sensors, random miss fire and a few for MAF. I changed the MAF and o2 sensors and the miss fire code went away, however the truck still won't accelerate the way it should and still stalls and has no codes. I thought maybe the fuel pedal switch (And I'm not a parts thrower atter), I thought fixed it.... still has a power loss and stalls every so often... enough that I can't drive it confidently. My next option is to check fuel pressure or change the TPS.... Maybe hoping someone here may have an idea before I even go that route.