Jeep Bucking/engine sputters

'98 Cherokee Sport, 4.0 I6, automatic

Right after a recent oil change (probably just a coincidence) my jeep started bucking intermittently while I am driving it. It idles irradically sometimes, but the idle is fine most of the time. The bucking almost seems like an engine sputter and doesn't seem to occur under any one driving condition, but it seems like I notice it more often under high engine load. The check engine light came on once but then turned off after one day. It has thrown trouble codes: P0107 and P0463 which according to Chiltons are "Manifold Absolute Pressure/Barometric Pressure Circuit low Input" and "Fuel Level Sending Unit Voltage too High". I couldn't find a vacum leak, but is this a possibility? Any suggestions or ideas would be highly appreciated.

Does the buck occure at or near the same RPM, might be TPS has a wear mark or a high resistance in it. RPM helps determin shifts and the corisponding spot might seem to move but really just happen in a small RPM band. Just a thought.
Can't help with the idle as i cant fix mine either.

I finally took it in to a dealorship for a diagnosis. Turns out my spark plug wires were arcing. Must have been really cheap wires. I put in some mopar plugs and wires and problem fixed. Hope this helps someone out there.