THE DARK SIDE.. 2.5L Hesitation and backfire

I recently had a 1994 mpi 2.5L YJ.. yes YJ fall in my lap. NO wrangler forum has members as badass as so heres my problem.
When i first got it she had 60 psi at the fuel rail causing it to backfire and hesitate under accel. I blew out the fuel lines and it was a clogged fuel return line that fixed it.
Now the psi is right at 31 but it has slowly returned to the old problems. If i push the gas pedal down 1/2 or so it will accel. smooth and slow. but when i give 2in. or more pedal to accel. faster, it boggs and backfires until above 2500rpm or so then smooths out and goes like hell. It is running rich at the exhaust tip and i had black creasote on the tip of the exhaust.
My fixes: not plugs or wires, fuel pressure at the rail, o2 sensor, idle air control valve, throttle position sensor.


IM LOST HERE!!!!!!!!!!!

thanks,
damn YJ

temp sensor will make it run rich, but almost sounds like timming.
witch if the temp sensor is bad , the puter would retard timming.
I would say check more sensors!!

can you test the temp sensor? and what readings would i look for? i think im running out of sensors to check!

also the temp guage reads from 180-210 during normal operation. goes up to 210 then temp guage rapidly drops to 180 till heat builds up again.. probably a sticky thermostat.

to check temp sensor as follows - unplug the sensor and when engine is cold should reed 7000 ihms or more, and when engine is hot it should reed less then 1000 ohms.

ok, will check that... I wont be able to do anything to my jeep till weekend after this. Anything else you can suggest?

more help.. anyone?