mostlikey the crank position sensor is acting up it will need checking, and check the torque convertor clutch solenoid, too. as this can also be the culprit. see possible causes below
yeah , I mean that couldve been the problem, most people wouldve done the same thing, at least you know you have that taken care of and will not have to worry about a pump for years to come, more than likely it wouldve came up in the near future anyway. excellent observation.