It revved up to 2k rpm immediately upon starting (my feet were no where near the gas peddle, it was all on its own) and took about 30 seconds before it eased itself down to just under 1k rpm. As soon as the rpm slowed I could hear a fast ticking from the passenger side of the engine. The CEL turned on, but I wont have a chance to get the code pulled until tuesday. Any ideas what it could be? Seems to be running fine other than the ticking.

It's a 99 cherokee sport 4.0 4x4.

 

lifter?

 

knock sensor? Idle air control sensor? crank positioning sensor maybe?

 

The fast ticking: if lifter related would change with RPM's. I'd guess its the evap solenoid ticking. It's normal. However, there could be a vac or evap leak causing that high RPM on start up. You should try to verify where noise is actually coming from. Could be TPS or IAC valve related. Bummer you can't pull codes till tues.