Here is the deal, I have a 2000 4.8 that keeps getting P0137 and P0157. I changed a rear 02, gutted the cats, replaced the intake gaskets (which did help it run better), and a few other things. When cold it runs very bad and in first gear as well as anything below 4000 it runs bad. Here is some freeze frame data:

Code P0137
100% throttle
3399 RPM
35.6% Engine Load
79.23 GR/Sec MAF
MAP sens 98 KPA
Coolant temp 199*
Short term fuel trim 1 0.8%
Long term trim 1 24.2%
Short term trim 2 0.8%
Long term trim 2 23.4%
Short term trim 3 -96.7%
Long term trim 3 -55.1%
Short term trim 4 -89.7%
Vehicle speed 80 mph
Fuel system 1 OPEN1
Fuel system 2 OPEN1

The CEL only seems to come on at full throttle but the truck runs bad all the time, worse when mentioned above. Any help would be much appreciated. Thanks,
-Evan