Geared Resto Co.

Hi all,

Trying to make some sense of a standalone configuration that I'm working on getting running in a project truck. The specs are:

-'08 LY6
-PSI conversion harness
-8 new injectors
-new fuel rail
-completely re-gasketed
-new timing chain
-new MAF
-new O2 sensors
-new GM cats

-4L80
-filter/re-seal

The truck starts and idles very nicely, and as long as I keep the throttle under around 20% it seems to run fairly well. Once I pass that 20% mark the engine completely falls on its face, almost as if the fuel is cut. It'll bog all the way back down to idle, all while sputtering and choking. As soon as I back out of the throttle and get back into that 0-20% range it'll build revs again.

I'm a bit stumped here. The entire fuel system is brand new and I'm seeing 60psi at the rail, so I don't think it's a fueling issue. Any input or suggestions? Not really sure how to proceed from here. I do have access to a fancy Snap-On diagnostic tool if any specific data would help.

Much appreciated in advance!