99 k2500 sub help. 454 runs rich/sputters

[Joe91M]

hey y'all, my wife's dd is giving me a headache right now. It's a 99 K2500 suburban with a 454 4L80E 246. It's currently throwing a keen code on both downstream O2 sensors. They are reading .02 volts across the board. Since they are showing lean, the truck is DUMPING fuel into itself. It's also seriously pressurizing the fuel tank. So far I've changed out plugs and wires, O2 downstream, and tried to find any possible vacuum leaks because my buddy thought it was worth a try and good to rule out. The misfire monitor hasn't tripped a code, however #1 has a pretty constant misfire between 70-190 counts a minute. #2#5#8 also misfire around 12 counts during heavy accel. Any ideas would be awesome. I have a new cap and rotor and I'm thinking I'm Donna do plugs again just to see what they look like after a week.

 

[thearborbarber]

I had a dirty maf once cause both 02 lean codes to be thrown.

 

[Joe91M]

Awesome. I'll have to check that next. My other thought was to try to unplug the sensors and see if the computer would revert to a basic mode

 

[Stephen Carter]

Does it still have cats? Had a camaro that on heavy acceleration would misfire, cut it out, problem solved

 

[Hogback Fabrication]

Injectors are a common issue on those

 

[Joe91M]

Still has a bone stock exhaust. Like I said, fuel pressure is good but I'm hoping it's not injectors. Is there an easy way to test them? I.E. Unplug each one and listen for lack of a change?