Hesitates when accelerating, rpms jump

Ok, so I switched my CPS for a problem I had. Since then I have an intermittent problem.

1. When I hit a bump from time to time (and I have my foot on the gas) the RPMs jump around wildly on the dash, there is no RPM increase in the engine.
2. Sometimes when accelerating the Jeep will hesitate or just sort of interrupt and do it in a very foul manner.

Might this be due to a faulty CPS or the CPS being installed in an incorrect manner?

The CPS was switched to a new one when trying to diagnose a no-start issue (the no-start was probably caused by a "cold" fuse not the CPS).

Always include your jeeps info in the OP...

If its a 97+ id say the gauges and hesitation are two different problems...
97+ is known for the gauge connections being oxidized and causing problems.

Id check for a bad ground or sensor wire in the engine compartment for the hesitation. Cheap crank sensors can cause problems too.

Sh*t, I got my info in my signature on other sites. Adding it now.

The hesitation always happens when the RPM gauge goes crazy. It always happens when I hit a bump or something.

Jeep Cherokee 1997 4.0 AW4

sounds like a loose ground