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Jeep Cherokee Grand Cherokee Engine and Performance Problems



  • I just experienced similar problems with my '93, so I changed electronics plus the fuel filter, with no luck. I bought a fuel pressure kit (hoses/gauges $15 @ auto stores) and found my fuel pressure was off by 50% (data in repair manual $20).

    After testing the fuel regulator (OK), I decided to change the fuel pump. This was no easy job, as my fuel pump is located INSIDE the fuel tank. Don't attempt this without assistance.

    You'll also need a floor jack, 3 ton car stands, upper body strength and lots of caution working around a gas tank! Call local auto stores, salvage or websearch for exact fuel pump match, so you'll need it in your hands. Of course, this means you'll have to take it off the road for these repairs. I used a self-service salvage yard, LKQ, and saved over $250 on the pump.

    The fuel pump has a LARGE plastic securing nut holding it to the tank. Use a wide blade screwdriver and hammer to gently tap it off. Be sure to replace the rubber seal with a new one (Jeep $15).

    I hope there is a solution for you somewhere above.
  • 2004 JGC Laredo 4.0L, 2WD, LHD, MTC, A/C and heating wouldn't turn on; turn signals wouldnt turn on either. Flashers do work, dealership stated that it was an inoperative heater blower motor, blower motor resistor module, and a inop multi-function switch. Replaced all. 10 minutes later, driving away the heater quit (nothing at all, not even cool air) and the turn signals quit also. Still not fixed. Today, the vehicle overheated while running in the opened garage (it is about 30 degree's here). This vehicle has not been run much lately, has NEVER overheated. All I can think of is a power surge or short on the A/C and the turn signals (a fuse was blown, no it's not the fuse). Maybe something electronic on the overheating (its not the thermostat or the pump....). Prior to this, NO ISSUES. Vehicle has about 58,000 miles, is garage kept, and maintained well. I think its an electronic bug somewhere. I know the first two issues are connected and now I think the third has joined the others. I've heard of a lot of issues with the Jeep but this is the first on my three problems (heater wont turn on, A?C; turn signals same, overheating...).
  • My 88 Cherokee 4.0 inline six cylinder, 5 speed manual, loses power when going up a hill whether the hill is a steep one or not. It's much worse at losing power on steep even loses power when downshifting to get more power.
    What could this be?
  • Hey, hope someone can help with this, 1993 Grand Cherokee 318, didn't start from one minute to the next, replaced the fuel filter, we have a good spark, all electrical works, reading the forums it seems to be the crankshaft position sensor which I bought. I found the electrical connector for the sensor by the dist cap, followed the wire to what feels to be the sensor, there is very little room to maneuvre your hand let alone tools, am I missing something ? It seems to be behind the engine block on the passenger side next to the distributor, can't visually see it just feel for it. I removed the passenger side Valve Cover, which is giving me a bit more room, but still can't see it. Am I on the right track ? :confuse:
  • tht828tht828 Posts: 4
    I'm having the same problem with my 2004 4.0 six cylinder. Haven't been able to find source yet either. If you find out the problem please post the cause, & I'll do the same.
  • 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 20 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 (almost like some type of pressure leak). The sound is louder and more prevalent when engine is cold. Sometimes disappears after driving a while, but other times it doesn't. The check engine light is also on. Took it to Jeep service twice, both times they say the computer is returning and invalid code. However when I took it to Autozone, they had a code that was related to emissions sensor.
    Any suggestions?
  • Took the Jeep to my mechanic, ends up being an intermittent faulty Fuel Pump, started 3 out of 5 times, after doing an entire tune-up. The Fuel Pump is in the Fuel Tank, typical lol :-), the fuel pump costs $ 374.00 (module actually), Oh well, it's running great now
  • I hope you can help me out..I was driving home and the first thing I noticed was that the heat coming out of my vents went cold and seconds later my gages were chirping at me. I pulled off the highway and noticed that both my oil pressure and temp gage were red. I popped the hood and noticed that the coolant was released by the pressure relief valve but that was it. I checked the fan belt - no problem. I waited for a while and then started it back up and went as far as I could until the temp gage came close to the red zone (the oil gage stayed high). I did this several times until I got home. The only other thing I noticed was the engine wouldn't start right away - I had to feather the gas pedal.
  • If you have good spark then the crank sensor is working. Are you checking for spark at the coil or the plug wires. Do you have good fuel pressure? Can you hear the fuel injectors chattering. Can you hear the fuel pump kick on when you turn the key to the on position or when it is cranking over?
  • Hi,
    Your problem sounds very like the one I have with my Jeep a 98/99 Cherokee with all the same suspicions as to symptoms. I have confirmed that it is not fuel pump, regulator or filter by hooking up a pressure gauge inside the car to the fuel rail. It stays at 50 psi when I get the problem. I also confirmed that it is not O2 sensor as this is operating within the expected voltage range. I am not sure whee to go next.

    Did you resolve your issue and if so what was the solution???


    Mike :confuse:
  • xmechxmech Posts: 90
    LOL! Sorry to throw this in here, but I've been lurking many other threads at Edmunds searching for a good mid-size sedan to replace my 2000 Grand Cherokee. One day I decided to see what's up in the Edmunds GC forums, and couldn't believe all the problems listed here!

    I've had 2 door lock actuators go bad, a siezed rear brake caliper, both rear axle seals leak(NEVER off-road), the interior lights mysteriously fade on and off with the alarm set, my water pump goes out October every 2 years, a transmission leak which will probably cost more than the car is worth to fix, and now my oil pressure gauge pegs at max pressure with the engine off... :sick:

    So I found it kind of humorous that they are looking for some 'satisfied' GC drivers. I guess other than the issues, I like my GC other than the MPG, nowadays. I'm sure there are satisfied owners out there, it was just funny to find that comment amongst all the problems. :D
  • tidestertidester Posts: 10,059
    they are looking for some 'satisfied' GC drivers ... it was just funny to find that comment amongst all the problems

    One might conclude that's what would make it newsworthy! ;)

    tidester, host
    SUVs and Smart Shopper
  • -additional info for #465...

    I replaced the water pump and it appears that the temp is under control but my oil pressure is still extremely high. I took it for a test ride and it stalled out after about 3 minutes. Right before it stalled I was having to feather the gas to keep the engine running.
  • xmechxmech Posts: 90
    Does your oil pressure show high with the engine off but the ignition switch on? Might just be a bad sending unit and nothing to do with it running bad.
  • I just checked - with the key in the ignition, the oil reads just above 40, after I start it up it goes up to 70. Early this morning, I let the jeep run in my garage for a while. When I first started it the it up, the engine would rev properly when I step on the gas pedal but after 5 minutes it would bog down when I stepped on the gas and then shoot up....any help?

    I was checking out some other web sites that discussed reasons why the vehicle would stall. A majority of the issues looked to be a bad crank shaft position sensor...
  • After 5 mins, the pressure creeped up to above to apprx. 73.

    I'm worried I might have blown my head gasket when my water pump stopped working (replacing the water pump was close to maxing out my mechanical abilities). Replacing the head gasket does not look easy...
  • xmechxmech Posts: 90
    Wow, head gasket?

    Well, I'm not a car mechanic by trade, but let's start from the beginning:

    What year/engine/miles do you have?

    Have to ask, so don't be offended, just have to know, have you been following the maintenance schedule at least a little? Replaced spark plugs, cap & rotor(if applicable), etc? Just have to ask as I know people who just run their cars until they die and wonder why it doesn't run without oil and such.

    Also, if you suspect a head gasket failure, is the oil milky from water? Or is there oil in the coolant system?

    Oh, and if the oil PSI shows 40 without the engine running you think you can trust it when the engine is running?
  • Hi all,

    My 2002 GC (inline 6) started making ticking and knocking noises about two months ago. Sometimes its a tick, sometimes a knock, and sometimes it sounds fine. I have had it into my mechanic twice and to the Jeep dealer once, but, of course all three times it ran fine. After talking with the service manager at the Jeep dealer, on his advise I changed the oil and added a container of Lucas oil additive. For a week or so after the oil change, there was little if any noise, then the noises gradually became more frequent. Then, several times while sitting at a traffic light, the oil pressure dropped almost to nothing, but promptly went back to normal as soon as I would pull away from the light, other times the oil pressure would remain up at idle. I bought it back to my mechanic (one of those times it would not make any funny sounds); he checked the oil for coolant (it was fine) and changed it, again adding an additive. After that second oil change, again everything was fine for perhaps a week or so, then the ticking started every now and then. Now, about 3 or 4 weeks after that second oil change, the knock comes back sometimes and the oil pressure has started running abnormally high, not high enough to turn on the check gauges light, but much higher than it used to run, almost reaching the "H" while accelerating. The Jeep service manager, my mechanic and two other ex-Jeep mechanics I have talked to are all at a loss as to the cause of the problem. Of course the service manager and the ex-jeep mech. who now has his own repair business both say I should put in a new engine.

    The Jeep has 168K miles on it and otherwise runs fine. Even when making noise there is no apparent loss of power, although, of course, I am treating it gently these days. Any ideas?


  • A bit more info and a question;

    The oil has been changed regularly, although a few times not till about 5K miles after the previous change.

    Does anyone have a thought on having the oil system flushed out. One mechanic recommended this (and, of course the Valvoline folks always suggest it), while others are neutral about it or do not recommend flushing it out.

    And, as for flushing the engine oil system out, how do they do it? I would be reluctant to have it done if it means running the engine with a solvent or chemical in it that thins the oil, but then, I am getting a bit desperate to solve this problem before I have a bearing seize up on me!

    Thanks again,

  • i have a 1997 grand cherokee V8 and i get around 17mpg, i have had the water pump replaced and the ac pump and i now have 200,000 miles on it and it is running great. i have a stroie to tell about this winter, my husband and i live on a mountain side with a pretty steep drive. This winter my husband came home from his job (he drives a 650 ford utility truck fully loaded with all tools and a crane, he was pulling a trailer behind it with his jetta on it and he could not quit make the hill. He decided he wanted me to pull him up a little bit of the hill to get him into our landing, i thought he was crazy, or he wanted to break my jeep. well he hooked up a strap to his truck and my jeep, we through a little gravel under our tires and i put the jeep in 4 low and believe it or not i pulled him and his truck and trailer up the hill and into our landing. The only regret is that we did not video tape it because it would have made a great comercial for jeep. Our camp neighbors could not believe it either they said if they had not been there to see it they would not have believed it. Please keep in mind that this is an older jeep, but it still has the get up and go that jeep is famous for. i just thought that this was amazing and i wanted to share it.

    Thanks : bren :)
  • tidestertidester Posts: 10,059
    I think that would have been a great commercial! But just be prepared. You may get a second chance. In a few days the ground hog will let us know how many days of winter are left. :)

    tidester, host
    SUVs and Smart Shopper
  • xmechxmech Posts: 90
    Unfortunately, I think I have to agree with the engine replacement idea. Of course, have a professional take a good look first, but it sounds like worn out bushings and stuff with all the knocking and noises it's doing.

    Good luck with it. :(
  • Hi, I am currently having the same problem with my 99 Jeep Grand Cherokee Limited. My mechanic has replaced 3 of my rocker arms so far and now decided to try changing the lifters. I was wondering if you ever solved this problem?
  • You have to understand that these have 3.73 ratio gears in the axels. that means that the propellershafts will turn 3.73 times before the tire turns once. that is what gives us more acceleration, passing , and towing power.
  • Hello billnick
    I know this is a old thread, I have the same problem with my 2001 JGC Laredo 8cyln. I did the same as your thread, when I cut a hole on the bottom of the head light housing all I found was a vacuum box of some kind! Have you heard this ?
    Thanks Don
  • clairwayclairway Posts: 1
    i just recently purchased a 01 GC for my nephew and after a week it is tapping kind of loud and starting to run hot..all fluids are full and it has new oil..when you go to take off , it kind of hesitates , but not from transmission..i took it to a respectedmechanic in town ,and according to his machine , the number 4 cylinder is not working / firing? he says its something internal of engine , and maybe a bad piston? he said it would be way cheaper getting a new motor installed , anyone have any idea what else this possibly could be , hopefully he is sounds like its coming from top half of motor , but im no mechanic..thanks
  • Solved for the moment!!!

    Seems the turn-signal, fanclutch, A/C, and the rear signal are all wired in series. When the rear brake light went out, the system overloaded, Ohms built up to the point to blow the fuze. Replaced first the tail light sockets and then the entire rear light assembly. Seems to be working for the moment.

    New issue, when going above 50 mph, the vehicle will sputter and act like its being flooded out, going to die. Really bad in overdrive. Runs great at slower speeds. Auto zone states check for a 'boogered' vacuum line.

    Someone start a Class Action Lawsuit about this vehicle!!!
  • gcristeagcristea Posts: 3
    Hey anyone--just purchased a '96 Cherokee with the 4.0 motor and 75K miles//vehicle seems to run well with good power and smoothness but am only getting about 13mpg overall which I think is low for this vehicle--am going to take it to my local mechanic for a general check---any thoughts on what he should check for or what is the usual cause for gas mileage problems//I have looked at the tailpipe and there is no black deposit//any help would be appreciated//thanks--George
  • trek87trek87 Posts: 49
    first check the cheap stuff - e.g., air filter, spark plugs. you could also go for a fuel injector cleaner service. even with the low mileage for this age vehicle, the plugs and injectors can still get gunked up over time. good luck.
  • On 3-18-09 - We too have a 2001 JGC Limited 4x4. Early a.m. waiting for school bus with my Grandson; the vehicle is in park & running, as with every morning. While sitting in park I noticed that the check engine light had come on and about that time the Jeep lurched forward as if it had came out of gear. We looked down, but it was still in park! Later on mid-day, went down our lane to the mailbox as always, came back to pull in my driveway towards the end of our home and as I placed it in park, the engine sped up dramatically, I looked up and I was still in motion and it very quickly hit the end of our home head-on. When I looked down in my shock and horror, it was still in park and I had to place it in reverse to remove it from the house. I was literally afraid to place it in park because I thought it may lurch forward again! Me being the woman driver that I am, going to my mailbox normally would not require a seat belt & I am an avid advocate of wearing your seat belt. However, because I didn't have it on, once I hit the house I came out of my seat (leather) hit the steering wheel & knocked the breath out of me; both knees hit the dash and indented it, breaking one of my knee caps; hit my head on the windshield area and blacked my eyes and severely bruising me all over. So there's damage to my home, my Jeep is totaled and I'm injured! Within less than 10 seconds, I went from being healthy, with a car and an undamaged home to this! Thanks Chrysler for not keeping auto owners of any kinds of issues that are detrimental to our well-being. We buy your vehicle out of good faith, however the same is not nearly bestowed back to the consumer!

    Needless to say, even though it didn't look like much damage, the insurance company has totaled my Jeep. The radiator and many of the components on the front of the motor are damaged, inasmuch as the front frame. The vehicle has had so many repairs once we paid it off in 2006; In December of 2007 a new $2750.00 Jasper transmission at 125,000 miles (now has only 26,000 miles on the new one; with a 100,000 mile warranty) New Heater Core; New Blower Switch; New Battery; New TPS sensor; New #2 Oxygen Sensor (there are four); New Tires; New Brakes & Rotors; New Blendors (Heat has been an issue for about 3 years); now the Outside Air Vent door has broken off & was laying on the blower motor preventing any heat from coming through my vents & it needs repaired;

    Any of you Jeep owners experienced all of this in three (3) years? I'm sure that anyone that owns a Jeep finds it attractive and versatile, however, it is a pain in the wallet once you've outlived your warranty. Of course, the warranty is a whole other issue and infatuation. Now they have a lifetime warranty on the drive train. Imagine that!!!

    Any views on buying your Jeep back and repairing it and/or parting it out? The interior is in great shape and has leather seats. Other than these issues, I've enjoyed the comfort and versatility. Its a shame I have to give up what is paid for.

    Thanks for any input ....apologies for the lengthiness of this post!

    :cry: :cry: :cry:
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