98 Jeep Grand Cherokee 4.0 4×4 Auto NO POWER

Posted in Winch
  • I have this Jeep I’ve been fixing up and outfitting for offroading, but I’ve realized I have no low end torque. I had some problems with the O2 sensors about 4 months ago, but solved that. The Jeep has a hard time staying in 4th gear on the interstate. If I hit a 5 degree incline or a gust of wind while driving 70 MPH it kicks into 3rd gear.

    I’ve also noticed that the temp runs hot. I stuck my finger in the washer fluid container the other day and it was steaming. It feels like I’m always driving around in a higher gear and need to downshift, but I’m actually in the low gear. I normally drive in 2WD beacuse it’s easier on the suspension / tires.

    I have the following on the Jeep…
    -31×10.50 MT
    -4.5″ lift (didn’t drop the t-case)
    -Throttle body spacer (doesn’t do jack)
    -Expedition rack
    -K&N air filter (doesn’t do jack)
    -Some stereo junk
    -rebuilt tranny about 2 years ago
    -I’m currently getting 11-13 MPG
    -No error codes (ABS light is on)
    -No custom gearing
    -Recently swapped engines
    -Recently changed plugs / wires / rotor / starter / alternator / exhaust manifold

    Anyone have any ideas why I feel like I’m driving a prius??? I can’t even spin the tires unless it’s raining and I’m on slick pavement!! I think right now I couldn’t even beat a geo metro in a race. If I turn on the AC I can’t even beat a 49cc scooter in a race. Maybe I need to switch to the V8. Thanks for the help.
    I did replace the O2 sensors as well as the Catalytic converter about 6 months back.

    Something about the heat just seems odd. This Jeep runs really hot, but the engine temp is generally cool. I’ve also noticed that tranny fluid bubbles out if I fill it to the normal level. I’ve been driving with it low because it doesn’t boil out this way (bad idea). It seems to be overheating.

    There are 6 Answers for "98 Jeep Grand Cherokee 4.0 4×4 Auto NO POWER"

    1. Hair Lover says:

      Sounds like a fuel problem.I would put some Lucas fuel treatment in it and some berrymans fuel treatmnet.You may also have a vaccum leak

    2. dr_cook76 says:

      You got a lot of meat on the sand there… might be the 4.0 doesn’t have enough.
      But on a mechanical side. I had the same truck and had a couple of problems with the electronics of the transmission. One resulting in a similar condition as yours. Don’t remember what it exactly was; but it came up on a scan. Try hooking it up to a dealer type scanner or a full dyno.

    3. Doug K says:

      Your first mistake when wanting to feel the power of your motor is having a 31″ tire with factory gears. Factory you have 3.55 gears, a 31″ tire would much rather prefer 3.91-4.10 gears. Next, with the 31″ tires and 3.55 gears, think of you walking and then you walking with a 500 pound stack of bricks on your back, you won’t like it and will feel the weight. Don’t get me wrong, nothing wrong with the 31″ on 3.55, it will be fine but anything over 31″ tires you’re going to want to regear. You have a stereo, does that include subs? there is some weight there. Also regarding your mpg, the fact you have a tire/gear setup that is hard on the motor, it has to work extra thus killing your MPG(this is also why you’re not feeling the low end torque from the start, the motor is struggling).

      You’re problem on the highway about downshifting, by the tire/gear combo you drop down a few hundred RPM at coasting, you may just not have the power in 4th gear to go up the hills or break through the wind.

    4. Josh B says:

      31′s will slow you down a hair…but not that much seeing that stock 23575R15 are 28.87 inches. If you had some O2 issues did you or have you ever replaced the catalytic converter?? The transmission issues the previous guy was speaking of are dirty or corroded shift solenoids. Also, your torque converter could be acting up. I hate to tick you off but I’ve seen way too many intakes full of crud thanks to a K&N filter…they are junk.
      Also to keep your 4.0 running strong read this….http://answers.yahoo.com/question/index;_ylt=Av8ZJSmIsYdROsFuEL1Kcpnty6IX;_ylv=3?qid=20090602100553AAcZDM7 ^(http://www.carparts21.com/goto/http://answers.yahoo.com/question/index;_ylt=Av8ZJSmIsYdROsFuEL1Kcpnty6IX;_ylv=3?qid=20090602100553AAcZDM7)

    5. Seahorse says:

      It is more than likely a fuel problem. Get the fuel line replaced.

    6. First off, your 4.0 has more than enough power to push tires up to 35 inches without a new gear set. To me, this seems like a transmission issue. The first thing to do is pull the pan and replace the fluid and filter. A treatment like TransX may help restore sticking syncro, and help clean any crud that may be built up in the system. I do think you will want to run a new gear set in the axles to help make up for the loss of the small amount of torque you will experience. I run the smaller 2.5l I4 in my XJ with 3.73 gears. I have no problems keeping up with traffic on the streets. The fact that you are puking out fluid tells me that the problem is defiantly in the transmission.
      Hey, but don’t take it from me, I am just an ASE mechanic that loves Jeep.

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