Last post on Oct 15, 2006 at 8:49 PM
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Jeep Liberty, SUV
#1366 of 2253 Jeep Liberty- hesitation problems described?
Oct 05, 2004 (10:46 am)
Recently, I'd noticed a lot of posts on the forum about a mysterious 'hesitation' while driving the Jeep Liberty. Scant details were provided, such as current conditions (going up hills, automatic or standard transmission, what rpm's during hesitation or immediately after, what size engine) or what speed they're going, etc. Having just purchased a brand new 2004 Jeep Liberty Sport, these posts concern me-- especially when they all tend to report the same problem. Usually, when a consistent problem arises from peoples trouble reports, it often suggests a consistent design flaw exists in a product.
I work in the computer industry, and a lot of my job is diagnosing reported problems from users who are usually unaware of design considerations, software, or have very little knowledge about how computers work in general. Often, these users will use terms which describe their perception of the problem, but might not accurately reflect what's actually going on. Or the language used can contain symantecal subtleties which might be perceived by a different user as something else.
After reading enough reports, I began to believe that I have been affected by this same 'hesitation', but I am perceiving it as something slightly different- in my perception, I equate it to a temporary 'lack of power'. I'm going to continue to refer to it as a 'hesitation' because now that I think I'm on the same page as everyone else, I'm happy to continue to refer to it as thus. My aim in posting my perception and opinion on this hesitation is to help out those who have been seeing this problem, and possibly give them some peace of mind.
The model that I own is the 3.7l , 6 cylinder automatic transmission Sport model. After owning it only a week, I noticed that when going up hill on a freeway at speeds of around 40-50mph and often trying to accelerate, the vehicle would begin to slow down or lose speed. I would give it more gas, and the vehicle would continue to slow down- which I believe can be perceived as the 'hesitation'. The vehicle doesn't immediately take off, or accelerate, it 'hesitates'. I would give it just a hair more gas, still no acceleration- vehicle continues to slow down. Finally I push the accelerator further (not to the floor by any means), the automatic transmission 'kicks down' to the next lower gear and takes off. This set of events could easily be perceived as 'hesitation'. At first I was concerned over this performance. But then I started really analyzing the problem, and continued to read professional reviews- and here's what I think the problem (if it can be called a problem) is:
The Jeep Liberty has a curb weight of over 4100lbs. This vehicle is heavier than almost everything in its class (compact SUV). The engine is a 216 horsepower engine. For instance, the Nissan XTerra, which is a physically larger vehicle has a curb weight of 3800 lbs. And a reading of XTerra owner and professional reviews suggest that the XTerra's main flaw is that it's way underpowered, making the supercharged version a MINIMUM requirement, bringing the vehicle to what it should have been from the first place. In the case of the liberty- the engine is powerful- but it NEEDS that power because of the strength and weight of the chassis. The automatic transmission in the Liberty is indeed slightly sluggish. The vehicle is designed to drop into overdrive arguably too soon when combined with the vehicles wight and power. When the vehicle drops to overdrive and is in the 40-50mph range, the RPM's are barely at 1500. The Jeep liberty simply does not have the power (at the 4100lb weight) to accelerate itself uphill (even a slight incline)in overdrive and at 1500 RPM's. Pushing the gas far enough to force it to drop to the next lower gear will kick the RPM'S up over 2000, and then the vehicle has the power to start accelerating. But this 'waiting period' where the transmission is 'figuring this out' is a little sluggish- and I believe elicits the description of 'hesitation'. Also, I tend to not be an overly aggressive driver, so my personal problem was that I simply wasn't giving it enough gas to force the vehicle to drop to the lower gear and get the thing moving up the hill.
To conclude, this is precisely why driver experiences will differ based on different driving styles. One recent post to this board indicated that she actually took the dealer out on a drive to PROVE that this occurred, and when he drove it, it never did, but as soon as she got behind the wheel, the hesitation was noticed. That's most likely because his driving style overcomes this tendency of the liberty to struggle through the 40-50mph range.
My conclusion is that there is no physical problem with the Liberty. It's merely a design 'quirk' that exists because of the combination of vehicle weight, transmission design, and engine power. My guess is that the same engine and transmission on a considerably lighter vehicle would experience none of this described hesitation. This would probably also explain why the respective service departments are FAILING to find anything wrong- because there is nothing really wrong. In fact, a professional review I had read referred to this problem in the most subtle of ways. It spoke of the need for the powerful engine due to the weight of the vehicle and said: "Maintaining highway speeds can be difficult[...]". What I believe they were referring to in a roundabout way is the very thing I described above. That when driving on a flat road at say, 50mph (and I see it even at 60mph at times) that you'll 'lose speed' suddently when going up a grade.
I'm anxious to talk to or exchange ideas with people and possibly run through some more 'scientific' tests- and record more variables such as RPM's, current speed, percentage incline (no matter how slight), number of passengers etc. My guess is that most of you can be rest assured that nothing serious is happening.
#1367 of 2253 Re: Help with Storing Owners Manual [franzia]
Oct 05, 2004 (10:52 am)
There's a slot above the actual glove compartment when you open the drawer. Dealer pointed it out to me and said it was often overlooked by customers. Slides back into the dash. The 2004 model DEFINITELY has it, I'm not sure about 2002 or '03 models.
#1368 of 2253 Engine update
Oct 06, 2004 (8:21 am)
I just got off the phone with the dealership.
They hear the noise but cannot determine the source.
As far as the rough idle it seems to be an issue with all 3.7.
Looking for some feedback on both points.
The engine has been a little rough since new, i have no issues if that is the way it runs.
But the noise or knocking sound does concern me.
#1369 of 2253 Re: Engine update [frank58]
Oct 06, 2004 (10:19 am)
I would argue that my two week old LIberty idle's a bit rough. It seems to be the natural way of the engine. The knocking sound would concern me. When you say 'rough', describe what 'rough' means to you.
Oct 07, 2004 (5:04 am)
Rough means I can feel it and when I look at the engine I can see it.
They found a historical miss fire in cylinder 6. But nothing showed up that day
#1371 of 2253 Jeep Liberty Problems
Oct 07, 2004 (6:25 am)
As far as the rough idle goes, the dealer told me it is due to stiff motor mounts-I have a 2003 3.7 limited.
Oct 07, 2004 (3:41 pm)
Mine too. I think it's just the nature of the engine. If I sit in mine while it idles, every few seconds, the whole jeep vibrates. Not dramatically, but you can feel it through the seat. If it were a cadillac, I might suspect a cylinder was misfiring. But the engine sounds ok, it just feels rough. All my acceleration and other things feel smooth.
For those of you wondering, you can get engine/computer error codes in your jeep. The way you do this is while the engine is off, press and hold your Trip Reset button, then turn the key to the ON position. Don't turn the engine on, just put the key to 'on' so all the instruments and electronics go on. Your dash will light up, all of your gauges go into a kind of 'test mode' where they move the full range in unison- then your display computer will count from 9 to 0. Following this I believe that a software revision comes up, followed by the most recent error code in the engine. I was given a link to a list of error codes, but it didn't work for me, so finding what the error codes mean is up to you. Let me know what you find.
#1373 of 2253 Re: Rough [jnaut]
Oct 07, 2004 (10:33 pm)
About the error codes:
On my 2003 Liberty Diesel I get= 'code 1.4' after all the tests are done. I don't know what this stands for, since the truck is working fine. I haven't yet come across the diesel codes. Maybe we will get to know more about them when the CRDs will be on your roads...
#1375 of 2253 Re: Rough [caribou1]
Oct 08, 2004 (8:49 am)
On my 2003 Liberty Diesel I get= 'code 1.4' after all the tests are done. I don't know what this stands for, since the truck is working fine
I believe that this is the software revision in your computer. I've heard that you can go to your dealer and get a new rev for your software- but I don't know if there are any restrictions on that.