Originally Posted by Rawkon
throttle position sensor
That's my guess too. That's the gizmo that reports to the computer how much you're stepping on the gas so if it gets intermittent (dirty inside) so it gives an eratic signal to the computer, the engine can stumble or accelerate roughly. If it is indeed a bad TPS which is caused when they wear inside and flakes of carbon interfere with the electrical contact, you can sometimes temporarily clear the problem by working the throttle back & forth 75-100 times which will temporarily clear off the carbon that is contaminating it internally. If that helps, then the problem is almost certainly being caused by a bad TPS.
One more thing you might try is using a can of Throttle Body cleaner to clean out the inside of the throttle body. If it's black and gunky inside, the engine won't run well. And part of that is another sensor 90 degrees CCW from the TPS called the Idle Air controller that when it gets dirty, it causes rough idle problems and occasionally acceleration issues.
The below shows you where all these gizmos are located. Either is easily removed for cleaning (only the IAC can be cleaned) or replacing (only the TPS, the IAC can be cleaned), just two small torx screws hold them to the throttle body.