CVO 10/13/2012The check engine light doesn't have to be ON to store a fault code.
Check the vehicle for fault codes to see if there are any sensors were involved to the malfunction of the engine.( Don't ignore this step )
1.Local auto parts stores such as Autozone ( not in California) or Advance Auto parts will scan and retrieve any diagnostic trouble codes ( dtc ) stored in the powertrain control module for free of charge..
2. Amazon.com has the code reader for less than $20.00 dollars.
3.Re-post the dtc's in here " answer question " for further assistance.
Note: we need the dtc's to identify the sensor, there are a dozen different sensors to operate the car.
Visit this site and see all the different sensors.
Navigate to this site and see the code reader
bnlpartee 11/18/2012my 2001 Jeep grand cherokee seems to be doing the same thing. As long as its cold and you make it thru the gears to drive it does great. Once you park it and leave again before its had time to completely cool off it shifts thru first and second, and thats as far as you get. The engine starts cutting out real bad, it doesn't stall but engine light starts flashing and your stuck in second gear running 2800 rpms at 43 mph, anything above that it cuts out until you let off the gas. The only error codes it is reading is 300, 301,302,303,304,305,306.
We have already replaced the spark plugs, coil rail, fuel filter, cam speed sensor, crank speed sensor, output speed sensor, changed the oil and air filters.
Any ideas would be great, we are stuck.