So I've had a new engine installed and I recently have been having idling problems. It always starts up just fine but revs up to 1200rpms by itself and then drops below 1000 and the jeep starts shaking like its had a misfire. This happens even when I start driving. I'll pull up to a stop light and watch the rpm gauge continue to rev up by itself while I'm holding the brake harder and harder to keep the jeep from driving off on its own. Another issue when I am driving is I get a very high pitched whistle when ever I give it more gas. If I let off the gas slightly, it goes away. Lastly, If I am driving on the highway and I get above 60mph, the engine misfires. I can shut it off and turn it back on and it runs fine. Here is a list of what I have already replaced:
-2 upper O2 Sensors and 1 lower O2 Sensor (ordered the wrong one)
-Throttle Position Sensor
-Crank Position Sensor
Note: I have also gotten codes for a small EVAP leak and will be purchasing a new EVAP System soon.
If anyone could help me diagnose this one I would greatly appreciate it.