It won't rev doesn't give us a lot to go on.

Please explain the problem in more detail.

Like "I'm sitting still with my foot on the brake and the torque converter lockup is keeping the motor from revving past 3,000 rpm." To this, we'd say totally normal.

Or "While driving the motor is bucking and the check engine light is flashing and it won't go above 3,000 rpm". Then we'd tell you other stuff.