2003 Ford Ranger 3.0 lean and no power!

I've got a 2003 ranger kicking my but! Bank 1&2 and both showing lean DTCs are lean can't remember what they are off the top of my head. At idle LT trims are +25 on both when given throttle bank one goes down to +5ish bank 2 goes to -14. Truck has no power when driving you give it throttle and falls right on its face. Poking around in the scanner I noticed on the cylinder contribution test at idle cylinder 4 5 6 drop out -18 roughly come back to 0 in and out constantly. Fuel pressure is 55-60 psi idle same while normal driving and WOT. Truck has been sitting for a few years due to this issue had a reman engine installed approximately 10k miles before this happened ans transmission Rebuild about 1500 miles before this started. (I specialize in transmissions repair and rebuild so bare with me on the diagnostic process here) I checked for vacuum leaks today and found none. I'm hung up on the cylinders dropping out in the cylinder contribution test as being the lack of power issue but I'm stuck as where to go from here. 

How does your mass air flow sensor grams per second look at wide open throttle? Have you taken a fuel sample since it’s been sitting for a bit? Could be injectors failing due to varnished fuel

Mass air flow checks out fine at idle normal driving and WOT. It's was Parked due to this issue customer drove it for a few days to run all old fuel out and filled up with new fuel before bringing it to me.. I'm not so worried about the lean condition as I am the lack of power. Should I do a compression test on bank 2 followed by a cylinder leak down test? Like I said previously the scanner show realitive compression low on bank 2 all 3 cylinders customer has had the lack of power issue since the engine was installed 

have you tested your intake vac for exhaust pluged or old rear o2 sensors test them

This screams internal vacuum leak to me.

Pinch off the PCV.

Remove the Oil filler cap and if its a neck style wrap a neoprene glove over it or simply just cover it with your hand.

Rev it up and check for suction.  There should be Zero suction at idle and off idle.

At idle LT trims are +25 on both when given throttle bank one goes down to +5ish bank 2 goes to -14

It is not enough to just look at LT trim. You need to consider ST, as well, and base your decisions on the TOTAL fuel trim.

Truck has no power when driving you give it throttle and falls right on its face. Poking around in the scanner I noticed on the cylinder contribution test at idle cylinder 4 5 6 drop out -18 roughly

As Lupe was suggesting, I would look into exhaust back pressure on Bank 2. An exhaust restriction will cause a rich reaction, with negative fuel trims.
If you can, remove an upstream O2 sensor on Bank 2 and install a pressure gauge. Raise the Idle to a steady 2500-3000 RPM's. Exhaust back-pressure should be less than 3 psi.  I like to see less than 2 psi. 3 psi, or more, is a problem.

@paul the PCV valve did turn out to be stuck open causing the lean code. As far as my no power problem it turns out the catalytic converters are stopped up! I pulled out both O2 sensors and and truck runs great for not having O2 sensors lol thanks everyone for your help and sharing your knowledge! This was a tough diag with there being nothing sticking out anywhere to say the cats where bad kinda weird. Unless it ran lean for so long and couldn't add enough fuel for the influx of air and ruined the cat? I think I'm thinking of that right of someone could better explain that to me I would greatly appreciate it!

@chad it was definitely an exhaust restriction not sure what caused it haven't pulled them yet to investigate its been this was since not long after the engine was installed

That is good to hear!!!  Alldata showed me an exhaust with a y-pipe and one cat!  Now your trims make sense!!!

Good thing Mr. Chad Coleman is on the ball!!!!