Jeep runs great at Idle and after 1800rpm but between 1000rpm and 18000rpm the motor surges and misfires in when in park, when driving it feels dead and then takes off hard after 1800rpm.

I also have Ripp headers with a custom tune from RPM extreme on a Diablo tuner.

Also after washing the motor the belt got very noisy and the sound changes or goes away temporarily if I spray water on it, so noisy I won’t drive it!

 

On the tune issue have you contacted rpm extreme?

On the noise where about is it coming from? Blower or drive pulley on engine?