99 XLT 4X4 4.0 bogging down, loss of power

[Ranger9909]

Hey folks.. I'm stumped. I have a 99 4.0 XLT 4X4 with about 138-139k miles. I bought it about 6 months ago and it was great. Recently, ive had a slew of issues. Ive thrown multiple codes, including generic misfire, misfire on 4, 5, 6, az well as others. Also, its thrown some o2 sensor codes, lack of heat on 02 sensor, ect.

Here are some 'physical' symptoms; start up the truck, drive a bit and everything is great. At a random stoplight, i take off and it bogs down. Hold the pedal to the floor and within 5-7 seconds it starts to get the power back.. but not for long. Does the same thing again.

When i turn the truck off at a stop light, and start it up again, it runs perfect again, for about 5 seconds.

This is hit and miss with this issue. Some days its horrible, some it runs like brand new.

Repairs so far: replaced the coil, new plugs and wires, fuel treatment, ect.

Any clues?

 

[2000StreetRod]

which 4.0L V6?

Do you have the OHV or SOHC V6?

When the engine is started the PCM runs in open loop while waiting for the O2 sensor heaters to warm up. If a heater to one of the pre-cat O2 sensors isn't working that needs to be fixed for the fuel trims to be correct. What is the actual DTC?