vibration under load and no power

[kirakitty]

96 ranger (B4000) ext cab 4.0L 4x4 auto. 135K miles

I had some problems with the 2 piece shaft, It vibrated real bad, I replaced the universals, carrier bearing, and on top of this the Driveshaft universals were out of phase. Unfortunatlly this also created stress on the slip joint which moved around like jello. Well I installed a 1 piece alluminum shaft and all new universals and the vibration I felt towards the back of the cab is gone. But what I have now is, a vibration under the front of the cab, It happens when I Jump on the gas. Not pedal to the metal, just to get to speed. If I baby it, the vibration is minimal. So it seems to be under load when it happens. What else should I be looking for. Tranny and motor mounts are good, I cant feel any play in the transfer case or tranny. I am thinking about the injectors and it is just running like poop under load. Any other thoughts of what it could be.

Thanks

 

[snake]

If you think it could be the engine, and you said it isn't running right- try some injector cleaner. Has it been tuned up lately? Maybe a fuel filter too. Could also be the torque converter if automatic. What about the front U-joint? Could be lots of stuff so we'd need better details of the problem to narrow it down.