i have a 03 4x4 ranger. when i am crusing and i try to accelerate to pass a another vehicle the truck starts shaking like it almost doesn't want to shift out of the O/Dgear (the rpms don't increase) for a second or two then when the rpms increase it feels rough. if i punch it from a stop the rpms jump up, but the acceleration isn't smooth and the shakes.

the shaking feels like a bad plug, but it doesn't run rough all the time.

 

Hi, welcome to the forum!

It sounds more like an engine problem to me. How long since the last tuneup? Have you pulled the plugs to check them? Scanned for codes? Is the MIL (Malfunction Indicator Light) on?

You can start with the simple things like that, and assuming the air and fuel filters are clean, you can clean the MAF and the throttle body, these are things that can contribute to power loss and rough running.