rebal14

Just bought this 2000 Grand Cherokee 4.7 and it ran fine coming back from Cal to Nevada, once here in what seems the heat of the day it will lose power and stall, when you turn the key to restart the gages will only come up to zero and not where they should be, it wont start as long as the gages are on zero no matter how many times you hit the key , then in what has usually been about 10 to 15 minutes the gages will go back to there normally reading when you hit the key and then it will start and run fine, during the malfunction I get a code saying "malfunction engine speed sensor" but once its running it shows no code, the closest thing I found was the crank position sensor and could fine no engine speed sensor, I changed it out and going for a test drive now in the heat of the day, the engine temp is normal and I can test drive at night and nothing will happen just seem to be around noon here, I dont see how the CPS could cause the gages to zero?

rebal14

Back after the test drive, went 54 miles across the desert, stopped a few times shut it off and it started and ran fine with no issues, then my daughter took it to the park, " it is her jeep" and bam! not once but three times the same thing only starting to get worst and shutting down at speed, not just a stop signs, also when I changed the sensor I also put some fuel system treatment in the tank and it was only half full, when we got back from the test drive we filled the tank which would delute the fuel treament, Iam starting to think fuel pump but dont understand the gage thing and what connection it would have to the fuel pump or the CPS for that matter