Alright after reading this post i am convinced that i have a very similar problem with my ranger as well. 2003 2wd xlt 3.0l flex.

When i want to drive accelerate normally my engine carry's out through the rpm's just fine and my transmission gives no problem....

BUT! as soon as i want to start passing other cars or suddenly pick up speed i would push down on the accelerator some more and my transmission would kick down one gear (as it is sopposed too) but once its in this gear and it starts going up to say 4000 rpm it suddenly starts kicking violently and it wont go past 4,000 rpm.

ANOTHER INTERESTING THING......is that when i decide i really want to push the pedal all the way down from say a dead stop....She will take off just fine and if i am already rolling then she would just kickdown a gear and continue....its when i am completely stepping on it that it does not buck around 4000.....i think to my self that its actually working...but when i get to around 5 ish it suddenly kicks back.....but for a very short moment.......and after that it continues perfectly fine and i can continue to speed up as much as i want ( until i hit that 92 mph limit of course)

Now you guys may be on to something here with the transmission idea...but i have another suggestion that i would like to throw out there....could this possibly have something to do with maybe some sort of safety feature similar to the rev limiter? because when i try to compare this problem to anything else the rev limiter is all i can think of seeing that when it reaches a certain rpm it suddenly starts to bounce around there not letting you go past it....could it be that something similar to this is happening and that is whats causing this big kicking feeling?

Blueranger1801, your problem sounds like a bad coil/coils or spark plug wires/plugs. I had two of three coils go open on my old 87 3.8L GM motor. It would drive great except when under heavy load. Two of the three coils were open internally on the high voltage side causing the generated spark to jump three gaps instead of the designed two (waste gate operation of coils, two plugs fire twice every crank rotation. One fires on power, the opposite one fires on exhause, for emmissions). After researching that I replaced those two open coils and never had another occurance of EXACTLY what you are describing. So, not knowing if your coil is a one piece, or sectional, I would check the internal resistance of each pair of coils, then the spark plug wiring, then the plugs (order of simplist to hardest).

Your situation DOES NOT sound like the slip-yolk problem we are experiencing.

to ranger69:: Ok thanks for the help. I dont want to start another thread in this post so i will pm you more about this.

Blueranger1801, reply sent! Good luck!

Does anyone know where the Transmission speed sensor is located? I have bought one, but have no idea where it goes... went to parts store, and no help.. got any help????