acceleration problems

well since my jeep is getting to be a constant problem child i thought id ask about the lastest problem. while accelerating i have to put the pedal to the floor for anything to happen. even while driving its to the floor or it putters, jerks, rpm's go down to idle. i ran the scan tool and i had an constant open loop in the 02 sensor and my thermostat (sp) was running cold just replace both with little to no change. its a 1989 jeep cherokee auto trans, 4.0 laredo. any help with what it could be would be great i need to be able to drive it again.

plugged catalytic converter maybe? do a back pressure test.

but i was told if these something pluggin the cat it will make noise from the engine vibrating

Test or change the O2 sensor.

i ran the scan tool said i had an open loop in the o2 sensor so i just replaced it 2 nights ago

It's an 89? What kind of scan tool do you have???

Sorry I misread your first post. It says you changed the O2 sensor already.

OK, there are a lot of possibilities. It definately sounds like a bad TPS.

I would test the TPS sensor next with an analog volt meter to see if it is working right. Should have 0.8 volts at idle from connection C to B on the three pin TPS connection. Test it with the power on, but engine off. Then as you manually move the accelerator the voltage should increase smothly up to something over 4 volts. If it is not a smooth volatge rise with a smooth movement of the accelerator then the TPS is bad. They wear out pretty fast acording to many here. It is just a carbon faced variable resistor and it wears.

Had the same problem. Turned out to be Fuel pump going bad. Couldn't build anymore than 20 psi. Changed it out (no need to drop tank) Fuel pressure 31psi at idle and 45psi with throttle.