Unsolved skipping problem

[nok-10]

I have a 2000 ohv explorer and it has a skip bad skip the cel says o2 sensor bank one and 2 are lean and random misfire cylinder number 4 and under a load the cel flashes . I've replaced plugs wire coil pack number 4 injector catalytic converters I just don't know what else's to check I haven't done a compression test or anything I need some help

 

[murdomino]

check for vacuum leaks first anytime both banks are running lean

 

[nok-10]

What that have anything to do with running so rough I mean it feels like I'm towing a car that keeps tapping its breaks

 

[nok-10]

Just drove it it idled fine but when I tried to take it down the road it had no power and was backfiring through the intake plenum

 

[Runnin'OnEmpty]

You might try cleaning the MAF sensor, and take
a look at the harmonic balancer. Check to see
if the rubber insulator is deformed and allowing
the pulley to move on the balancer hub.