Idling problem

Normal idle speed is about 650 rpms, and when you click on the A/C it may rise to 750 rpms. You may have a large vacuum leak. Check the vacuum line that runs from the cruise control over to the intake manifold. Or any other missing vacuum lines or open vacuum ports. Check for "hissing", ruptured brake diaphragm, leaking air. Look for sticking throttle cable, throttle body. Then scan for codes....turn the key from Off to On three times quickly without starting the motor. Stop at "On" and fault codes will display at the odometer display. It will show "done" when done. Google the codes and fix accordingly. Yes, 1500 rpms is fast. Makes my Jeep go 55mph in top gear/overdrive.