No check engine light
2004 larado 4.0
150,000

The problem only occurs upsteep graded at approx. 55 to 65 mph. When I'm at highway speed and I come to a steep long incline(Colorado) I have a hard time building rpm's , gas pedal feels stiff, if I push hard on the gas it with down shift rather hard and then build rpm's and speed.

New plugs
New fuel pump
new fuel filter


Anyone else have this problem? Suggestion's??

 

Engine is getting a bit tired, I know mine is at 216K. I just downshift by locking out O/D. Rpms stay reasonable. After all, 3rd gear is direct.

 

Not very helpful..

 

Hey, you asked for suggestions, I gave you one. After all, you're pulling 4000 lbs with 195 hp. What do you expect? It ain't a 5.0 Mustang, ya know?

The 4.0 makes max torque at 4000 rpm, not the 2000 you're running at 60 mph. Using wide throttle at low rpm will cook the valves, it it hasn't already.

Do a compression check.

 

The easiest way to improve that problem would be a gear swap to 3.73's, but not really cost effective.

 

Interesting. I have a Cherokee Country, 1996 4.0 with 313,000 miles, and it responds very well on any kind of incline I've attempted so far.

I think the OP has a legitimate concern. I agree that a compression check might be warranted.

 

My 1998 Cherokee 4.0 took inclines great, so I know this vehicle has similar capabilities, it is lighter then the 1998 and should not struggle like it does uphill

I will do a compression check and see if that helps me determine the root cause of the issue,

My gut feeling is saying somthing in the transmission, or possibly shift patterns is off??

 

Let us know what that compression check shows, okay? Or whatever else you find...

 

I think I know what the problem is. It's not shifting out of O/D when the load requires it to. This is a problem that happens all the time with the 42re and I've not been able to fix it on my WJ. When it does decide to downshift, it goes to 2nd for a brief moment, then goes to 3rd. I've had it not make up it's mind coming on an on-ramp when I need more power until I give it a touch too much pedal, then it goes to 1st! screams for a second, then goes to 2nd. I've replaced the governor sensor, overdrive and torque converter solenoid pack, and speed sensor. Nothing seems to fix it so I just shift it myself when I need it. I've been told the TCM needs to be reprogrammed, but I'm not wasting any more money on it when it works fine shifted manually.

 

Compression test results:

c1- 147psi
c2- 148psi
c3- 150psi
c4- 149psi
c5- 146psi
c6- 145psi

results look good on compression test,

 

Is this a new problem or has this vehicle done it since you've owned it?

Max

 

Since I have owned it.

 

If you haven't gave it a full tune up try that,But keep in mind your xj weighed about 3300lbs while your wj weights in at 3800 to 4k depending its options.And both use a different trans so its probably geared a little different also.

 

 

Can't compare WJ to XJ. 42re vs AW4, Dana 35 vs Chry 8.25 and the XJ weighs less. I own both and my 99 XJ is a rocket compared to my '04 WJ.