Originally Posted by Extinct

Ok, good test on swapping left and right. That tells us the 02 is good, and whatever the problem is seems to be located either on bank 2 of the engine or in the bank 2 circuitry. Your fuel trims indicate the ECU is throwing all the fuel it can at bank 2, but it still cannot raise the voltage. It appears as your engine warms up it gets progressively leaner on that side. Note with the same amount of fuel a warm engine should actually be richer than a cold one, so yours is actually working in reverse. I doubt it is just one cylinder, that likely would not have this big of an impact without a miss. It would be strange indeed to have partially plugged injectors on one side only, however we may consider swapping left to right injectors just to rule out an injector issue - lets come back to that. The power steering booster and PCV valve vacuum ports are directly over the bank 2 intake manifold junction at the main front intake plenum tube, although it would not be directly isolated to that bank, if those were leaking air they might have an outsized influence on that bank. You could pull both off and plug them just to do a test and see if it changes. It is possible your power brake booster has a hole in it causing a vacuum leak without you knowing it. Other potential leaks on that side include the intake gaskets and injector o-rings, although if you did not change anything recently those are unlikely to have this size effect. I pretty sure you can rule out bad coils/wires/plugs - those would cause a rich condition not a lean one.

I would recommend plugging those vacuum lines and see what happens. If that does not solve the issue I would probably swap injectors left to right just rule that out, then I would consider an ECU swap (I have the benefit of 4 running trucks and three spare ECU's). You could buy a used ECU/BCU/Cluster combo off of ebay to test with and just resell it for what you paid for it if you don't need it - basically free test parts.

Let us know what you find out.

Originally Posted by Extinct

Ok, maybe I missed it earlier when you said you had a miss. Based on the miss and the wicked lean condition, now I am guessing you have a plugged/dead injector on bank two. You can remove the injectors, crank the engine, watch them squirt. make sure all squirt. Or swap left and right. Also, I just noticed you have three of these. You might want swap EC/BCUU's with one of the other ones. If you don't move the truck it won't mess up the clusters. If you need to drive to test you should move the cluster two otherwise the ODO will flash.

Originally Posted by GarySpringfield

I was probably unlear on the miss, it will occur once the code is thrown, but not before. Since I replaced the sensor, it hasn't thrown a code even though the S1 voltage drops to zero...so it's not currently missing.

I'll yank the injectors first thing in the morning and report back. Thank you for all the help!
(My boys took the other D2's to the lake, but I'll have them back Monday if I end up needing to swap out the ECU packages)

Originally Posted by Extinct

Wait, your problem was on bank 2 before, now it jumped to bank 1? Did you move injectors left to right?