I have made the same thread in 3rd gen elect. but no answers. OK guys I have a good one for you. Have a buddy with an 06 LBZ, calls me and says his truck is not running right. He lives a bit from me so he takes it to a different dealer. I went over yesterday to see what I could find. Nothing that I could see was wrong other than the truck is being a PITA. The probelm--When taking off from a stop, if you nut it the truck goes to 2,000 RPM and stops pulling and does not shift out of 1st gear. Feels just like your fuel filter being plugged. If you let off the pedal a bit it will hit 2nd then same thing and so on. The stupid part of it is if you go easy on the pedal tell you get about mid why through 4th gear and nut it it goes like hell. The only thing that I could find that was odd is when in the problem area the commanded fuel rail pressure is only 6,670. Lets say I was in 1st and nut from a stop. She goes up to about 2,000 RPM, FRP commanded only reads 6,670, APP sensor 100%, MAF 103 g/s. Never tried it with the trans in T/H mode. If I commanded it with the TECH 2 to upshift it would but some problem in the next gear. I took several Snapshots and went through the PIDs and couldn't find anything. The truck started doing this after the other dealer had installed a tune with efi live or hp tuners I don't know which one they are using. I would love to see what yall think could be the problem. I am thinking something in the tune is screwed. Also if you are easy on the pedal the FRP command will go up higher, I saw 14,000 psi. Also I held the truck in the problem area for sometime and NEVER got a DTC. Buddy says the CEL has never be on either. What do you think?

First off I is no expert. But i will put my two cents in. If i understand right there is a tune still in the truck. Why not pull that tune out and download a stock tune back in and try the truck. If it runs okay then you will know its just the tune. Hope you figure it out.

I thought about that but he said no because if I put the factory programming in it the tune will be lost. He likes the tune when the truck is running right.

Take off the fuel lines and check for blockage or a piece of rubber acting has a check valve in the supply. Just a thought

why not take it back to the dealer that installed it and say hey, look you messed something up, fix it.

Sounds like you are in a fuel pressure limp mode. And it also sounds like it is due to the tuning. If there is a screwed up number in the fuel pressure tables (like the 6000 psi demanded you mentioned) and fuel pressure is too high above or below that it will put you in an engine protection mode. On the LBZ the tune is set up different than the older trucks like my LLY. LLY's act the way you describe when they throw a P1093 - which puts them in engine protection mode.

I thought about that but he said no because if I put the factory programming in it the tune will be lost. He likes the tune when the truck is running right.
read it before you write to it,save it and load original,and see

The only why I can set the truck back to stock is with the tech 2 and tis 2000. I don't have efi Live or hp tuner nor do I know how to us either of them. If I put it back to stock it will be just that.

Sounds like you are in a fuel pressure limp mode. And it also sounds like it is due to the tuning. If there is a screwed up number in the fuel pressure tables (like the 6000 psi demanded you mentioned) and fuel pressure is too high above or below that it will put you in an engine protection mode. On the LBZ the tune is set up different than the older trucks like my LLY. LLY's act the way you describe when they throw a P1093 - which puts them in engine protection mode.
thanks for the info. I thought the same thing when driving it but it would not through the code.

I wouldnt screw with it, tell him to take it back where the tune was put in. It seems there would be a warranty on the tune. He would be better off getting another PCM for the tune and put his original PCM back to stock IMO.

Sorry i didn't mention it but whoever he paid to tune it should be looking at it for free to be sure it isn't anything they did. If they are using EFI Live they would be able to put the tune back on it for him (I would think for free - it takes 5 minutes) after you load it to stock for troubleshooting. We will load stock tunes on for people to take their trucks in for warranty work then load our tune back on when they're ready - all for free.

Thanks for every ones advise. I called him today and told him to take it back to them and have them put it back to stock. Then we will kniw if it is the tunning or the truck. I am thinking tunning still but we shall see.