I had multiple codes and managed to get rid of all of them except a cylinder 3 misfire and rubbing lean on both banks I replaced 02, MAF, water pump, battery, fuel filter and other small things trying to figure out my problem but still can’t figure it out

 

Lean code doesn't not mean engine is actually running Lean
The computer calculates how much fuel it needs to add to the engine at current RPM and throttle position, millisecond by millisecond
It then looks at O2 sensor to see if there is too much or too little Oxygen in the Exhaust, too much O2 means a Lean burn, so computer adds more fuel the next millisecond and keeps doing that until O2 level in exhaust is correct
If it has to add more than 15% more fuel than calculated it sets a Lean code to notify driver of the issue, but at no time is the engine actually running Lean computer adds the extra fuel so it doesn't

Lean on Both sides of a "V" engine can indicate a few things
Upper intake vacuum leak(lower intake leak would only effect one side), should have higher than normal idle
Dirty MAF sensor
Low fuel pressure, 2000 3.0l should run 55psi fuel pressure, test it
Clogged exhaust, after "Y" pipe, would also have limited RPMs at higher speeds

Unlikely to be O2 sensors unless you had a lean code on one side for awhile, and then got other side showing lean, 2000 should be on its 3rd set of O2s in any case
Having two O2 sensors fail at exactly the same time would be long odds, lol


The dual Lean codes AND hard to start would point more towards fuel pressure issue
Rangers have no fuel pressure sensor, computer just expects 55psi, if its lower then it sets Lean codes, on BOTH sides, because it's calculations are based on the fuel amount coming out of each injector at 55psi, lower pressure means less fuel sprays out, so Lean

There is a pressure test port on the engine, a schrader valve(like a tires air valve), works the same way, press the pin and fuel should squirt out, be careful
You can rent a tester and some autoparts stores loan them out, free

System should hold pressure above 30psi for MONTHS AND MONTHS, for start up
Then once engine is started, pressure should be 55-65psi, raise RPMs to 2,500 and hold there, pressure should hold, if its slowly dropping pump is weak

2000 Ranger will have both the fuel pump AND the Fuel Pressure Regulator(FPR) on the fuel pump assembly in the gas tank, either can cause lower pressure at the engine/injectors