I have a 93 ranger with the 4.0 v6. The truck starts fine, idles ok.. sometimes the idle jumps but just a little. When I start in 1st gear the truck runs great, as soon as i shift into 2nd gear i have a loss of power. The truck hesitates until almost full throttle and then it jumps and comes alive! Its got great power once I get past the sticky spot.
The truck throws a check engine light every once in a while but i cant relate it to anything. Plus, every time I take it to oreily to get the code checked, it wont read a code and just says that its unable to retrieve any information.

I have replaced all of these in the past couple of months:
Fuel Filter on side rail under drivers side
Mass air flow sensor
Spark Plugs and Wires
Throttle Position Sensor TPS
Ignition Coil (or coil pack i'm not sure of the correct name)
Air Filter
And i have ran lots of sea foam through the truck hoping it was a clogged injector.

Does anyone have a clue? My next step was going to be O2 sensors

Thanks
Blake

Pull plugs and check the ceramic for cracks or knicks, also gap them properly if you didn't before.

Could be clogged cat too...those tend to show themselves when the truck is under load.

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'01 XLT disguised as a '03 Fx4 Level II.