A Check Engine Light may illuminate indicating a "Cylinder #3 Misfire." This normally occurs in hot weather after the vehicle has been driven, parked for ten to twenty minutes, and then restarted. Heat from the exhaust vaporizes fuel inside the #3 fuel injector and causes the misfire. Installing an insulator sleeve normally lowers the temperature enough so the fuel will not vaporize.Google+
Car Problem Reports
Jeep Grand Cherokee Check Engine Light due to cylinder #3 misfire
Jeep Grand Cherokee Problem
Engines Affected: 4.0L 6 Cylinder, 4.7L V8
Average Mileage: 122,500 mi (96,000 mi - 140,000 mi)
I have seen the same problem with my jeep, had the car for about 9 years now and other than now it was a great car. the car struggles to start in the morning will start on the second sometimes 3rd try. and it will run fine for about 20 minutes, will start pulling alittle like it's not getting enough gas. the bigger problem seems to be if i stop and turn off the car if I restart before it completetly cools down is will not only strugle to start but run rough and will almost all the time have missfires. I have repalce fuel pump, injectors, plugs and coil pack it has made a small improvement but still continues to have the problems. If i let it cool down completetly and them start, it will run fine for 20 minutes again.
Tried that...still does the same thing. Does a weird idle and will not let you go more than maybe 10 miles an hour if that. Replaced like the service noticed said...still doing it.
I have random misfires in all 6 cylinders, especially in #4,#5 and #6. I also have a small evap sys leak that has been inspected down to removing the hitch,bumper and gas tank. I ran out of money and still have the problems. I bought it this way