Codes 137 and 173 running rich

[choatecostoms]

1993 ranger 3.0 4x4
My truck does not throw an engine light but runs super rich and only gets about 8mpg. The truck seems to run fine while driving and has about as much power as you could expect from the 3.0, Running a koer test it comes back with codes 137 and 173, bank 1 and 2 rich. I have checked and re checked everything I can think of, I have also replaced a bunch of things.

New o2 sensors, fuel filter, distributor/cap/rotor, wires, spark plugs, coil, thermostat, ECT, IAC, and injectors. Also has new cam, lifters, pushrods and timing chain. Double checked cam timing as well.

I have verified voltages to/from TPS and MAF sensors, checked for voltage drops and continuity across sensors/wires. verified grounds and even added a couple. Injector resistance tests good through pcm connector and you can hear each fire while running. Timing is at 10 btdc with pip unplugged and advances when you plug it back in.

Fuel pressure is at 38 koeo and 32 koer pull the FPR vacuum it jumps to 40. Pressure holds with key off also.

I even tried a remand PCM with no change.

I got the powertrain/emissions bible for 1993 and also the vacuum/wiring manual for the 93 ranger. I have exhausted everything in those manuals with the equipment I have and am at a stand still now. There has to be something i am missing. Any ideas would be much appreciated.

 

[Bgunner]

Any leaks in either the air intake tube or exhaust before the O2 sensors? There should be 3 O2 sensors on that motor, one in each down pipe and one before the cat. Any leaks before the cat will mess with your air /fuel mix.

Have you checked the intake gaskets?

 

[choatecostoms]

There's only 2 o2 sensors on this truck, checked intake tube no leaks. No leaks in exhaust either. I am about to pressurize the intake and check for leaks with soapy water as I have been un able to find any leaks via carb cleaner. I did however find the modulator on the trans failed and was leaking trans fluid into the motor through vacuum line, capped that off for now and it runs slightly better but nothing notable.
One more thing to add bank 1 o2 is not switching it stays high so I will be checking wiring again there. Tried swapping o2 sensors with no change there.

 

[choatecostoms]

No leaks found with pressure either.