In need of a little aid and assistance please

I just purchased a 2001 Dodge Durango 4wd with 140,xxx miles on it. My issue is that whenever I accelerate it hesistates and if I am going at a high speed like on the interstate or expressway it sometimes slows down (drastically) if I’m going uphill. What can be causing this?

If you didn’t have this vehicle inspected by your mechanic before you bought it, you’re overdue to have the vehicle thoroughly inspected and diagnosed by a mechanic you’ve selected and hired.

+1 to Whitey’s comments.

And, unless the OP has hard copies of the maintenance records for this vehicle, then he has to assume that none of the required maintenance has ever been done, and needs to have everything specified for the 90k/120k maintenance intervals performed a.s.a.p.

It is entirely possible that the problems are the result of lax or non-existent maintenance, but even if bringing it up to date on maintenance doesn’t cure the current problems, diagnosing the exact problem will be far easier if spark plugs, fuel filter, air filter, and other maintenance items are up to date.

first off - what they ^^ said

but this:

“whenever I accelerate it hesistates”

I call spark plugs… or spark plug wires…

^
A weak fuel pump is another possibility…

Or a plugged catalytic converter.

I agree with Whitey.
There are countless reasons why an engine would develop power problems. Without more information, it’s impossible to guess. It really does need to be look at hands-on by a mechanic.

The good news, OP, is that your car has an Onboard Diagnostic System that can help a qualified mechanic get to the cause. And the chances are excellent that it’ll be readily repairable without tearing the engine apart. If you were working on the car yourself, I’d recommend getting the codes read, but since you’re not, you may as well just bring it into the shop.

Sincere best.
TSM