I have a 2001 Ranger 3.0 V6 131k 4x4 and it seems to lack power. I have to put the pedal to the floor just to keep speed on the highway. I know there's not a ton of power in the first place, but it's getting to the point where RPMs are jumping every five miles or so just to keep a steady speed. Transmission was just rebuilt last week, new ignition coil/spark plugs/ignition wires, oil change/filter.

 

You may have more than one problem. Were you having these problems Before it was worked on, or are these new problems that began after the tranny work, or parts replacement????

Do you have a CEL lit???? If so, most autoparts stores will scan the computer for trouble codes at no cost, then post All trouble code Numbers, as they can offer up good trouble shooting clues.

With the mileage on this ride a good bit of scheduled maintenance is due, some of which you've already done, But you didn't say if the fuel & air filter, PCV valve, or O2 sensors have been replaced, or if you've done a fuel pressure & flow rate over time test, to check out the fuel delivery system & fuel pump????

If the tranny is still slipping, check the tranny fluid level on level ground, with it fully warmed up after say a 10 mile out & back drive & right after shifting into All gears, including "R", ending in "P", or "N".

If the fluid level is ok, check your paperwork to make sure the shop put in Mercon-V fluid.

If that checks out ok, take it back to the shop & have them scan the tranny computer for trouble codes, because if its slipping at high speed, it'll damage/glaze over, the clutch pack friction surface. So it sounds like something still isn't right with the tranny, don't delay in having it checked out. BTW, why did the tranny have to be rebuilt????

Give the forum some more clues & maybe we can offer up a better guess on where best to look for an answer to your woes.

 

I am showing no codes CEL or O/D off. the transmission was rebuilt because of a worn torque converter clutch and for the price he gave me he said it'd be better to have the whole trannie rebuilt. He replaced with mercon V, fluid level is good and no slippage, it shifts great.

From the list you gave me i've replaced the air filter. Not sure how to do a fuel pressure & flow rate test can you give me some pointers?

I've noticed it for a few months now, but today it seemed even more overly sensitive to the drive. I originally just attributed it to the sharp inclines on the highway and the small engine, but it seems to be out of whack now.

 

With it running, but lacking power to the point you have to foor the go pedal to keep up with traffic & no CEL lit, it suggests a fuel delivery/starvation problem. So if the fuel filter has never been replaced, its Way over due, by a factor of about 4, so if its plugged up & restricting fuel flow volume over time, the engine just won't go any faster unless the fuel flow can keep up with demand.
It'll also over work the fuel pump & cause it to give up the ghost sooner. So if the fuel filter has never been replaced, get er done, as it was part of your scheduled 90K maintanance.

If changing the fuel filter doesn't fix it, to read fuel pressure, there is a schrader valve, covered by a cap, usually black, on the fuel rail, for us to hook up a fuel pressure gauge & from that we can also measure fuel delivery rate over time, by directing fuel flow into a measured container. If you've never done this, do some online searches on how to safely & accurately do it.

If the upstream O2 sensors have never been replaced, I'd also seriously consider getting that done also, as it can improve fuel mileage & engine response to throttle settings, from faster switching response feedback to the computer, so it can keep fuel trim in proper balance. All a vicious circle!!!!

Keep us posted on your trouble shoot.