17th Dec 2004, 08:05

If your problem turned out to be with the emissions system, then perhaps you have already had it fixed. However, the root of the problem may be a buildup of carbon deposits. Chrysler Service Bulletin #0900303 explains just such a problem. I believe that the buildup of carbon could cause not only cylinder misfire, but also your emissions system Check Engine codes. Hope the information helps.

21st Jan 2005, 10:43

Regarding engine check light on: Your problem could simply be a vapor lock on one or more the injectors caused by overheating because the heat shield (insulation) is not lodged properly. It happened on my 2001 Cherokee. The dealer mechanic told me I needed a valve job costing $700-800. I knew my engine was running very well other than for this occasional "check engine light on" problem that occurred when the engine was hotter than usual. Lodging the heat shield properly solved the problem. The dealer in question is rated five-star!!!???

Good luck!

4th Mar 2005, 19:28

Check Engine light often came on our 2001 Jeep Cherokee Sport (60k miles), I always took it in for service when that happened. Usually it's nothing major, this time, it's a crack in cylinder cap, costing me $2k to fix. Chrysler is not being very cooperative to help out since my warranty is over. This is my second Jeep, I take very good care of the car and I am disapointed with this problem and especially with Chrysler's decision not to help. My suggestion is not to ignore those check engine lights and check it right away.

16th Mar 2005, 10:49

Thank you all for the great info! I have done my research on this problem with the engine light. If you take your Jeep into AutoZone they will check the error code for you at no charge. Turned out that my engine light came on because of an emissions control leak, which can come from a loose gas cap.

I still wanted the engine light to turn off so I bought an OBD 2 Check Engine Light Code Reader OBD2 OBDII II on ebay for $35. This great little device will not only check the error code for you, but it will also reset the engine light.

13th Mar 2007, 22:51

I have a 2001 Jeep sport 4.0 Liter 4 wheel drive automatic.

My engine light and airbag lights come on once in a while after driving. I had it in a few times to the shop and paid for diagnostics, they really could not fix it, after vapor problem, gas tank cap not on right, misfire on 1 cylinder, still lights coming on. I knocked with my hand on the instrument plastic cover and the lights go off. I told the repair shop they checked again and told me the computer is bad and could cost $1000 to install a new one.

I used my hand to knock at the plastic cover to fix the problem. Also when the lights come on usually no instruments are working.

Not really a good thing from Chrysler not fixing it right, otherwise I like the car very much and I got 97,000 miles on it. It is a quick Jeep.

Thanks,

Peter

22nd Mar 2007, 13:29

I recently purchased a 2001 Sport. The check engine light came on after having a rough restart. The code said misfires in 1 and 6 (free check at Auto Zone - thanks for the tip!) so I headed to the dealer. They suggested a 90k tune-up, but their work only fixed the engine light until I got home. Since then I have talked with a mechanic who says that it may be a weak alternator, needing to put out a perfect 14.4 volts at the battery, that is causing the computer to run slightly slower than normal; he said it may also be responsible for the rough restarts. I will check that next.

It is a fun truck and great to get around in.

29th Mar 2007, 22:10

I have a 2001 Cherokee with a check engine light on also. The code that turned on the light is a multi-cylinder misfire. After driving my Jeep on a warm or hot day and shutting it off for a short while (15-20 minutes) and then try to start it again, it will vapor lock and run very rough. I have a friend that is a very good mechanic and he told me that because there is no return from the fuel rail to the tank, that when I shut my Jeep off when it's hot, the fuel boils in the rail creating a vapor. Then, when I restart the engine, the vapor has to be purged through the injectors before the fuel, causing the rough idle and misfire. After the vapor is purged, the engine runs great. Now that I know what the problem is, I have just been dealing with it.

3rd Apr 2007, 15:40

I bought a 2003 jeep cherokee in Nov. '06 and I just took it in a few weeks ago to have some minor maintenance done, such as, oil change, transmission filter and fluid change and a new air filter. We just got back from a trip and the day after we returned the OBDii light came on. I've checked the manual and it says that it has something to do with the emissions control. I have kept a very careful eye on it. The manual says that if the light is blinking that it can lead to severe damage to the catalytic converter. My question is whether this is something that I need to be really concerned about or not. I traded in a '97 Ford Aerostar that I drove with the same light on for more than 4 years without a problem. It's manual though did not say anything about possible catalytic damage. Any suggestions on what I should do.

23rd Apr 2007, 10:26

I have a 1999 Jeep Cherokee Sport. I have not had any big problems with it until recently. My Jeep has about 100,000 miles on it. I have had a cylinder 1 miss-fire for about 4 months now. I have taken my Jeep to about 4 different places, and they have all done various things to it. They all have their idea of why my Jeep light is coming on. But like most of you, after the mechanic “fixes” the problem, the light comes on again. I have had my injectors replaced, my o-rings, spark plugs and wire on all cylinders, a engine flush, and the list goes on. I am still getting a cylinder 1 miss-fire. I am sick of paying mechanics to “fix” my problem only to have it happen again 2 hour later. Does anyone have any ideas on why this might be happening? I also notice that when my Jeep is idle it runs a little rough. However, when I push on the gas and goes above 5 mph the roughness subsides. If you have any advices, please post it.

Thanks!

24th Jul 2007, 12:08

Can anyone tell us why the stalling happens for 15-20 minutes? We just replaced a cam sensor. Is there a fuel filter relay fuse???

30th Oct 2007, 10:32

My 01' Jeep Cherokee Limited engine light is also coming on and it take a long crank before starting. It has been getting misfires on multiple cynd.

I had it serviced and they ask for carbon cleaning and new fuel pump - done. A month later the engine light is back on. I took it to a different dealer - since my mechanic can't figure it out. The dealer told me to to do the carbon cleaning and add a fuel pump - not!

Does anyone have any idea what causing this. Temperature sensor? O2 sensor is OK. Help!