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Very Infrequent, Sudden Jerking
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=58295		 Page 1 of 2
Author:  CTCRD [ Mon Jan 17, 2011 7:44 pm ]
Post subject:  Very Infrequent, Sudden Jerking
I've had my '05 Liberty CRD for about 9 months now. Maybe once every 6 weeks or so, I will be happily cruising along when all of a sudden, my Jeep will jerk somewhat violently like I hit a pothole or something. After checking the rearview to verify I did NOT hit anything, I settle back in and everything is normal again.

It happens mostly at highway speeds... usually around 55 mph. But it has happened with my cruise set in the low 70s, too. I was thinking it happened around 55 as if it were downshifting because it is accompanied by a spike in rpm. And it does feel a lot like when I was learning to drive stick and let the clutch out too quickly. (Who knew I could even do this to an automatic?! :oops: ). But that doesn't explain it at the higher speeds. It's infrequent with regular driving, but on a 800 mile road trip last summer, it probably happened 3 times. But I'll never be able to reproduce it for a mechanic.

I installed the GDE eco tune about a month after I bought it. But it did happen once before I did so. It did have the TC recall with the previous owner.

Any ideas? Doesn't sound like anything I've seen described here so far.
Author:  ATXKJ [ Mon Jan 17, 2011 8:23 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
Do you have a Scangauge plugged in?
it overloads the databus and kicks the tranny out of overdrive (randomly)

(and your rpm spike/jerk is the tranny kicking out of overdrive into 1:1)
Author:  GreenDieselEngineering [ Mon Jan 17, 2011 8:52 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
If the rpm is flaring, it certainly sounds like the trans going in a default mode (3rd gear lockup). After the event occurs will the trans upshift and rpm drop back down or does it require you to shut off vehicle for a minute to perform correctly? If it is trans related you will most likely need a dealer scan tool to check the codes. Sometimes exposed wiring can exhibit this behavior and that can take a lifetime to find. When was the last service to the trans? ie. how many miles since a fluid change?
Author:  CTCRD [ Mon Jan 17, 2011 10:25 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
As a matter of fact, I do have a scanguage! I guess I'll be ditching that until I need to scan a code! Assuming that's the issue, thanks for the info!
Author:  CATCRD [ Tue Jan 18, 2011 10:00 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
My scangauge did that too. Scary as heII.
Author:  nursecosmo [ Tue Jan 18, 2011 10:54 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
All scanners seem to do it if you leave them plugged in.
Author:  BlackLibertyCRD [ Wed Jan 19, 2011 1:22 am ]
Post subject:  Re: Very Infrequent, Sudden Jerking
I keep the creader plugged in with no problem. It there to clear the orm code. I never unplug it even if it sits a week.
Author:  Quiksilver [ Wed Jan 19, 2011 7:51 am ]
Post subject:  Re: Very Infrequent, Sudden Jerking
BlackLibertyCRD wrote:
I keep the creader plugged in with no problem. It there to clear the orm code. I never unplug it even if it sits a week.



Which model do you have exactly?

is it this one?

http://cgi.ebay.com/ebaymotors/CREADER- ... 008wt_1167

edit - Well i ordered it anyway - for that price how bad can it be....
Author:  OldSkull [ Wed Jan 19, 2011 10:48 am ]
Post subject:  Re: Very Infrequent, Sudden Jerking
There is 6 generation of Creader but are they fully Us CRD version compatible?? Got no clue...
I already write to Launch USA support for more info....

http://www.automotive-diagnostic-tools.com/Launch-Creader-V-OBDII-Auto-Scanner-p/lau-301050049.htm

http://www.launchtechusa.com/assets/products/CreaderVI.pdf
Author:  BlackLibertyCRD [ Wed Jan 19, 2011 11:39 am ]
Post subject:  Re: Very Infrequent, Sudden Jerking
Quiksilver wrote:
BlackLibertyCRD wrote:
I keep the creader plugged in with no problem. It there to clear the orm code. I never unplug it even if it sits a week.



Which model do you have exactly?

is it this one?

http://cgi.ebay.com/ebaymotors/CREADER- ... 008wt_1167

edit - Well i ordered it anyway - for that price how bad can it be....


Yep, thats the one, I plug it in without the cord.
Author:  CTCRD [ Thu Feb 24, 2011 7:38 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
I think my previous post from earlier today disappeared...

I thought I was out of the woods after disconnecting my Scanguage. But this week, the issue has returned so I'm getting it about a half dozen times a day. Taking it to a mechanic tomorrow, altho it hasn't happened to me today yet now that I've made an appt.

GDE, the rpms to subside again after a few seconds. I'm not sure when the tranny was last serviced. I've had it 9 months and I believe it was up to date on maint. schedule when I bought it. It's got 83k miles.
Author:  CTCRD [ Mon Feb 28, 2011 10:50 am ]
Post subject:  Re: Very Infrequent, Sudden Jerking
Well.... the mechanic said there was some kind of notice out there about the (OEM?) fuel filter I had. Apparently, it can allow air in the line which, he said, can create all kinds of havoc and, possibly, the behavior I was experiencing. Since they were not able to reproduce it, that's the working hypothesis at this point. Sounds like a stretch to me. But only time will tell, I guess. He did say air in the line can also cause hard starting in cold weather and I definitely have been experiencing that, as well, even tho I just had new plugs and relay installed.
Author:  ATXKJ [ Mon Feb 28, 2011 9:22 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
Well there are a lot of posts about air-in-fuel, running rough and Limp mode
however it doesn't normally kick the tranny out of OD (which is what your description sounds like)

It doesn't hurt to get the new fuel head and fix that ~ $100 and includes a new filter

would be interesting to know if it helps.
Author:  CTCRD [ Tue Mar 01, 2011 11:30 am ]
Post subject:  Re: Very Infrequent, Sudden Jerking
$100? They charged me $400. :? This is not a dealership.... guys that have a good rep and I've trusted for years. Did I get shafted?

It did not fix the issue. Happened every couple minutes on my drive home last night. It happens anywhere over 35 mph.... so doesn't that rule out anything specific to overdrive?
Author:  bhc04 [ Tue Mar 01, 2011 1:45 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
CTCRD wrote:
$100? They charged me $400. :? This is not a dealership.... guys that have a good rep and I've trusted for years. Did I get shafted?

It did not fix the issue. Happened every couple minutes on my drive home last night. It happens anywhere over 35 mph.... so doesn't that rule out anything specific to overdrive?


If I get this straight, Dealership charged you $400. for what? Replacing fuel filter and head? Did you get an invoice showing what they did?
Author:  CTCRD [ Tue Mar 01, 2011 3:46 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
Actually, I should relax til I get the itemized bill. I haven't actually settled up with them yet. $400 would include time spent trying to diagnose the problem, scanning for trans codes, and then the parts and labor for changing the fuel filter.
Author:  ATXKJ [ Tue Mar 01, 2011 8:55 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
well $400 for troubleshooting and replacing a $100 part isn't that unusual.

If it's not only 'cruising at highway speeds' - then the air in fuel starts making more sense
easiest check is to pump the pump on top of the fuel head - if it's soft, needs 2-3 pumps to get hard - it has air in it. now the entire fuel system is a vacuum from the engine back to the tank - and the most likely air leak is the head - specifically the heater plug on the head - but you can also have air leaks in the rest of the line - including the connectors at the tank - best combo fix for that is to add a lift pump at the tank - it gets rid of air

Some folks are finding other problems after that - but new fuel head and lift pumps are the most likely - after that you start having to troubleshoot harder issues
Author:  CTCRD [ Mon Mar 07, 2011 7:10 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
They charged me $150 for the filter. They replaced tranny fluid and transfer case fluid. The case fluid was pretty dirty. When they gave it back to me, they said it was still jerking but was less severe. They asked me to drive it a couple days and see if it smoothed out.

I agree the jerking is less severe and happens less frequently. But they also were not able to pull any codes for the tranny. So, I took it to Kennedy Transmission and the guy was able to pull codes P0944 (Loss of prime), P0884 (Power Up at Speed), and P0049 which may or may not be turbo turbine overspeed.

Loss of prime was quickly diagnosed because he found there was NO tranny fluid on the dipstick!! It appears the other mechanic may have drained it and forgotten to fill again. Had to put a full 4.5 quarts in! I will drive it a few more days and take it in to check the level again to confirm it's not just leaking it all. But there is no evidence of leaking at this point. The codes were cleared, so we'll also see if they show up again.
Author:  CTCRD [ Sat Oct 08, 2011 2:50 pm ]
Post subject:  Re: Very Infrequent, Sudden Jerking
For the record, the issue turned out to be a frayed wire bringing power to the ECU. Since this was one of the first things that should have been checked given the codes that were thrown, the dealer agreed to eat most of the repair costs.
Author:  DOC4444 [ Mon Oct 10, 2011 9:57 am ]
Post subject:  Re: Very Infrequent, Sudden Jerking
Can you post a picture of exactly where the harness was chaffed?

DOC
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