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Jeep Cherokee Grand Cherokee Engine and Performance Problems



  • I have an ongoing ignition issue no spark in 1 and 6 I replaced the coil pack and the pcm I had the pcm flashed at the dealer and checked the cam posistion sensor and crank posistion sensor omhed all wires and injector pulse is good .Any Ideas?
  • I have a 2001 Jeep Grand Cherokee Limited (4.7) with 75000 miles on it. Anytime I accelerate over 10 miles an hour a high pitch squeak strats. Multiple letting the air o0ut of a balloon slowly by ten and thats what it sounds like. Sounds alot like a belt but it only does it over 10mph and all the belts are good. I took the tire and brakes off lifted it up and ran it off the ground. The noise was still there. I got close enough to narrow the noise down to the front axle on the passenger side. I have had no mechanically problems with this vehicle at all. Any suggestions what this could be?
  • I'am sure most of you have heard this before. I have a 1999 Grand Cherokee V-8 that has plenty of power but rotten gas mileage. With the cost of gas I'am willing to sacrifice some power to get better fuel economy. Has any one had any success with any of the chips that are available and does a non restrictive air filter help
  • I have a 2001 Grand Cherokee Laredo and started hearing a very high-pitched sound that occurs when I decel (let off the gas) at speeds above 15 mph. When I press the gas pedal and accelerate, it disappears. It also disappears when I slow down below 10-15 mph or when sitting idle. It's not metal against metal (such as rotors/brakes) or anything like that. Sounds like a really 10x steam kettle.
    Any suggestions?
  • I have been checking out this forum and can find several people that are having similar problems with their jeep but not quite the same as us. We have a 97 Grand Cherokee Lerado, the problem we have is this. Each day when you first get in it you can drive normal for about 2-3 miles. Then all of a sudden the rpm's will go up and down, the motor acts like it wants to shut off. It runs like crap for about 1/2 -1 mile at a very slow speed. Once you get past this you are fine for the rest of the day, it won't happen again and the jeep runs great.....until the next day. We started by replacing the crank position sensor, followed that with the front oxigen sensor, replaced the plugs & wires, replaced the coolant sensor and finally replaced the pickup coil sensor in the distributer (along with caps and rotors). We even removed the cables from the battery for a time thinking that maybe that would re-set the computer memory somehow. It's still doing it! We thought it might be temperature related since it just happens the first time you get in it for the day, but why (if it's freezing out) would it not do it after it sat for 8 hours during a normal days work? The engine has to be cold then too. We are totally confused as to why this happens only once a day.
    On another note: we do have problems with out auto-on lights, they flicker as you go down the road. If we turn it to manual position we can override that but then the light on the light switch itself will still go on and off. We're thinking we just need to replace the switch for that, is that right? The two couldn't be related, could they? Any suggestions?
  • xscoutxscout Posts: 141
    I can't say my problem with my 1997 Grand Cherokee was exactly like yours, but it was similar. Car would start OK in the morning and then later as I was driving down the road it would start to run like you describe. In between episodes, car would run perfect. This would usually occur most every day but not always. Sometimes it would do this for short periods on and off all the way to work and sometimes it would just get stuck in this mode for most of the trip. I was always able to restart it if it shut down, usually with ease, sometimes not. And it could occur more than once in the day. I ended up replacing the PCM after doing the position sensor route to no avail. Check your connections on Your PCM to make sure they are clean and tight. If you do have to do the PCM, it will run you about $250 for a rebuilt with warranty if you do the switch out yourself. Make sure it is pre-programed, they may need your VIN# when you order it. It is a very easy job.
  • 5213252132 Posts: 62
    I got the same problem (and the same Jeep), well, I wouldn't call it a problem since it did it when it was new. It sounds like the front differential is making that sound. Do you have 4WD?
  • Has anyone seen performance comparisons between the new for 2008 4.7 V8 and the Hemi option? The 4.7 V8 for 2008 is a completely new design rated at 305 HP vs the Hemi's 335HP. The engines torque ratings are not that far apart either. I have a new JGC with the 4.7. It is not broken in yet and it is very quick, quiet and smooth. I have to be careful in local traffic when taking off from a traffic light I quickly find myself at 40+ MPH with very little effort. It would be interesting to see a performance comparison. Thanks.
  • I need to find the location of the oil pressure sensor on a 2000 Jeep Grang Cherokee. I have a high (4.0) reading with the ignition on. I turn off the ignition and it will drop to 0. Upon turning the ignition on (without the motor started) it will jump to 80 pp. What is going on???? Where is the sensor located??
  • tuggajbtuggajb Posts: 646
    mounted right above oil filter
  • skateaskatea Posts: 1

    I have a grand cherokee 1998, 4.0 L. When I am driving the engine shuts down and I just restart and it does ok for a while. The Dealer changed the distributor cap and roter, cleaned the injectors and throttle body and it is still the same if I drive and the RPM goes above 2000 for awhile, the engine shuts off and it starts again but why does it do that? Please help.
  • My first post here.

    My 98 Cherokee has developed a problem when running along not under load (flat open highway) it will miss sputter off and on. This does not seem to be affected by temp and is intermittant. Gas mileage has been affected as well. It has just rolled over 100K mi's and has had no other issues.

    Thanks, John
  • Hi,

    I drive a 2001 Jeep Cherokee, automatic transmission, 4.0L. My check engine light has been coming on and off for the past year. In all instances except the very first, the light came on while idling.

    January 2007: Light comes on upon starting the car. Code read catalyst efficiency below threshold. Cat was clean, so I replaced the O2 sensors.
    9/24/2007: I had a vacuum leak repaired and the light was turned off.
    10/4/2007: The mechanic adjusted "something" for no charge, and the light went off.
    11/21/2007: Light came on, but I went out of town and didn't have it serviced until 12/1/2007. Code read catalyst efficiency below threshold. My O2 sensors and cat looked fine, so the mechanic didn't think I needed to replace them. Mechanic turned light off.
    12/9/2007: Light came on, but I didn't have a chance to bring it in. It was off upon starting the car on 12/12/2007.
    12/14/2007: Light came on, but was off upon starting the car on 12/18/2007. That same day, while idling, it came on again and was on until about 12/28.
    1/18/2007: Light comes on again, and has been on since then, except for a brief 10 minute period between the time I started my car this morning, and when I idled at a traffic light.

    Does ANYONE have any idea what's going on? I've been to the mechanic more times than I can care to count. The code always reads catalyst inefficiency, but my sensors and cat are all clean.

    Thanks so much for any insight you can give.
  • I'm glad you found the problem that has been ailing by heep for a few months now. Question- Where is the upstream o2 sensor?
  • Hey,
    We just bought an 08' GC 3.0 diesel, only has about 400km on it. I am noticing that at highway speeds of 110km/h (about 70 mph) the engine is at 2500 rpm. This seems too high, we are in "D", don't have tow/haul on, it almost seems like it hasn't kicked in to overdrive. Even after an hour drive same thing. The temp is -10C, so it's not too cold.
    This is our first GC, not sure if this is normal or not.
    Can anyone help us out, is something wrong???
  • There's not too many diesels out there. They don't even sell them in New York State probably due to emission standards. If it is of any help to you my 08 JGC with the 4.7 V8 indicates approximately 2,000 RPM @ 70 MPH.
  • jim203jim203 Posts: 1
    Can anyone help. I replaced the waterpump on my jeep and when I went to start it, I heard a grinding noise when I turned on the ignition. It sounded like the fan blade had hit the plastic cowl. I immediately checked back under the hood and everything looked fine. I tried turning it over again and didn't hear the grinding noise, but the car wouldn't start. By reading numerous blogs and forums I attempted to find the problem. I checked the coil wire and I am not getting spark. I tried the tricks with the alarm system, no luck. I ran a diagnostic check reading the blinking lights and got a 54 which showed crank position sensor. I had it towed to a mechanic and he changed the cps which didn't help. Now he wants to try changing the crank position sensor to the tune of $300, with no guarantee of it fixing the problem. Could I have done something in the changing of the water pump to cause this. Thanks for your help.
  • leo01leo01 Posts: 3
    I have a 2000 grand cherokee and the radiator fan won't stop running even when the car is off. replaced relay , temp sensor and thermostat. Any ideas
  • xscoutxscout Posts: 141
    How long does it run? It is designed to run by temperature, not by wether the car is running or not. It is normal for it to run for a short while after the car is turned off. Of course if it is draining your battery that a defect.
  • hello, I have a 2001 jeep grand Cherokee limited wheel drive with a 4.7. I recently had a bent exhaust valve in #7 cylinder. The guide to one of the secondary chains broke and i jumped time. I took it apart, had a valve job done to that head , then put it back together with a new gasket kit. I also put new plugs in it. It runs like crap, like its running on 7 cylinders. I did a compression test and all 4 cylinders on that side have close to 150. the check engine light is on sometimes bu not much and when i took it to auto zone to get the code it came up bad O2 sensor on #1 Bank and that it was running lean. I'm not sure which bank is the #1. It wont idle on its own hardly ever, and lacks power tremendously. I checked the coil packs by unbolting them, putting a plug in them and holding them by the valve cover to see if it arcs, and they all are. It seems to be running very rich now, as it smokes a little black smoke sometimes. I think it is a fuel or fire problem, but not sure where to begin. Could the O2 sensor make it run that bad? Thanks Dave
  • i have a 94 jeep cherokee sport that is overheating at idle. it has a new thermostat, flushed cooling system, new hoses. The pressure was tested and its good. however the jeep has 2 fans. one is connected to the pully and one is electric for the A/C. When i have the ac on it doesnt overheat as quickly. does anyone know what could be wrong with it. it runs great considering it has 175K.
  • The electric fan isn't just for the A/C, and it sounds as if the electric fan isn't working at all. It is run by a coolant temp. sensor which, of course, turns it on at a specific temp. While idling, listen for it to come on, especially once the engine is warmed up. If it never comes on, that sensor would be the first thing to check. If the sensor isn't the problem, it has to be the fan itself.
  • My 2000 JGC will blow hot air from the AC after driving for over 45 minutes or so. Usually after stopping and the engine cools, when I start up again the AC will blow cold then after a while start to blow hot again. Any ideas?
  • tuggajbtuggajb Posts: 646
    poss the thermo clutch on the engine fan has gone bad when cold fan dosn't turn as fast when hot fan turns faster to chack run engine to temp sut off take hand and turn fan should be hard to turn if not change clutch
  • tuggajbtuggajb Posts: 646
    sounds as if ac coil is frezzing up pos low on ac fluid have them check that
  • i have a grand cherekee .

    the thign is vibrating at 70 miles per hour.

    anyone know what may it may be

    thnaks :sick:
  • where is the sensor? I will have it changed out if thats the case.
  • can you educate me about the fans? Mine has two. The main fan connected to the belt! is that suppose to engage? Mine isnt. its at one speed. I noticed that my dads toyota fan engages when you first start it. Is mine suppose to do that. also my electric fan engages only when the a/c pump is on.(defrost or A/C) How do i find which one is screwed up and where are these sensors at?
  • Sounds like you're low on freon. Have it checked.
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