Continued - Left bank misfiring thread

[68dodge500]

Well, spark knock (or the loud rythmic metal ping noise on accelation passed half throttle) is back with a vengence. Cylinder number 6 or 8. Pulled plugs on right bank, all were brownish, looked fine, #8 though was sooty. Fuel pressure test shows 35 avg. at key on, engine idle, and 2500rpm. Turn engine off and pressure stays until I hit the pressure release button on the tester. Timing is as good as it can be, sure of it.

Truck still runs sluggish/horrible under load at 2200rpm-2800rpm but makes it to 80mph with no problem. If I floor the gas pedal problem clears up until I let off, or if I drop the truck into 3rd gear out of overdrive it drive smoother, but still not great under accelation. Engine at idle is fine, strong sounding, and no "spark knock" type sounds.

Truck exhaust is loud and clunking off the right bank, so I thought perhaps the cat was gone again or the exhaust was clogged putting to much back pressure on that side of the engine. I dropped the exhaust, cranked and no change in problems. The truck is throwing code 44, 45, and 48 with no check engine light. And yes the CEL bulb works. The IACV (code 48) is new and adjusted, and I have working o2 sensors.

I am very close to parking this truck and buying a 2003 discovery with 86k that is near my work. Please help me get this problem solved.