Can someone interpret a freeze frame?

[yournamehere018]

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

[mean05]

if you gutted the cats then changing the rear o2 is a complete waste...the 137 and 157 codes are rear o2 codes...everything else in the scan looks fine...i can help you fix this just let me know when you're ready

[GasGuzzler]

79.23 GR/Sec MAF

Seems really low for 3300 RPM at 80 MPH. Is the MAF stock?

Long term trim 1 24.2%
Long term trim 2 23.4%

Both of these are way off, should be close to 0 no more than +/-10% IMO

Short term trim 3 -96.7%
Long term trim 3 -55.1%
Short term trim 4 -89.7%

Not sure what kind of scanner this is but GM doesn't use trims 3 and 4...never heard of if and it's not on a TechII. May be just another name for something. At any rate fuel trims on the 50-90 range is weird but like I said, I've never even heard of trims 3 and 4.

I really don't think the codes and the problem are related as mean05 mentioned. If the cats are gutted forget those codes and concentrate on fixing the drive issue.

[oleshifty]

Rear 02s/cats are JUST emission related, shouldn't affect anything noticeable

[RedHeartbeat]

if you're not getting into closed loop you probably have bad 02 sensors up front. They may be reading but reading poorly. You really need to put the readings up against a wideband for comparison. You should be into closed loop by about 2 minutes from the time the engine starts, mine gets in there in about a minute. Have you run leaded racing fuel in it or some fuel additives? Is your water temp gauge reading properly?

[GasGuzzler]

Yeah but WOT it's always open loop on the scanner.

[yournamehere018]

Well I don't know what the deal is but after I changed the intake gasket it gave me trouble for a couple days and then one night it back fired really bad and the light came on with the same codes. Now the light went out on its own and the truck runs 5 times better. No complaints here though.

[GasGuzzler]

Check the fuel pressure. With LTFT's in the 20's and a backfire it might be low.

[yournamehere018]

I checked it before I changed the fuel filter and came up with a steady 50 psi. I need to check it again, and maybe a volume test. Do you know what kind of volume it should push?

[GasGuzzler]

There are no specs I know of. Too many variables I assume. 50 is too low.