Stepping on the Gas, car lurches.

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Beth

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:eek: Has anyone had this problem? My car also bucks when I put it in reverse. Dealership can't find anything wrong with it. Some people say it is normal but how can that be none of my other cars ever lurched forward or bucked backward!

Beth Van Nostrand(blarg)
 

hyde

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Lurching and Bucking?
Can you give us a bit more details on exactly what you are experiencing?
My KJ was jumpy at first, and ****** a lot in the beginning, overtime it lost that.
 

Beth

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When I step on the brake from a red light I feel like the car shifts into fist. Then when I back on into my driveway no hill my car bucks. I have taken it to the service station but they just can't find anything wrong with it.

Thanks,

Beth

Lurching and Bucking?
Can you give us a bit more details on exactly what you are experiencing?
My KJ was jumpy at first, and ****** a lot in the beginning, overtime it lost that.
 

2003KJ

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When I step on the brake from a red light I feel like the car shifts into fist. Then when I back on into my driveway no hill my car bucks. I have taken it to the service station but they just can't find anything wrong with it.

Thanks,

Beth

Lurching and Bucking?
Can you give us a bit more details on exactly what you are experiencing?
My KJ was jumpy at first, and ****** a lot in the beginning, overtime it lost that.

I've noticed both of what you're describing (I think). Only, when I take my foot off of the brake from a light, and step on the gas, I can feel it lurch a bit. I figure it's just slack in the drivetrain. Done it since almost day one (doesn't happen all the time) and I've had no problems.

As for bucking when in reverse, thats normal, but more noticeable on hills.
 

ShafferNY

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I currently have this with my jeep. It's intermittant. I think I also have a sticky caliper on the rear driver's side. I'm thinking that the sticky caliper is causing the rear axle to wrap under acceleration and braking.
 

tylot3

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I had this problem and I took it into the Jeep dealer, they ended up replacing the pinion gear.
 

Alejandro

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Well, I reflect this exact problem... a sort of buck when stopping at red lights, but intermittently, it tends to be infrequent. Not only so, but shifting is more noticeable than an average vehicle and feels mildly rugged shifting from 1st to 2nd to 3rd.

I have a '04 KJ Sport, 3.7l, automatic, 122km, Selec-Trac transfer case.
I have only recently purchased the vehicle and have not done any personal maintenance.
 

LibertyTC

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Ok...42RLE... some of what folks are describing here is called hesitation in shifting back into first gear after stopping. Takes a second to get ready into first gear, and feels like a push forward a bit, when it finally shifts into first gear again, while brakes are on.
OR: You Stop. Then you when you step on gas there is nothing until it lurches forward as it has slept, and then decides to shift first gear, with a bit of a clunk. (now higher rpm engage)
What is the problem? Combination of situations if you ask me. First off had it into dealer, they installed some updated instructions into TCM (torque converter module) (shift points re-learned set differently?)
Obviously this 42RLE aint the brightest kid on the block. (valve body & torque converter)
It acts like a turbo 350 (TH350C)that is a bit low on ****** fluid. (higher pressure required to shift back into first, more fluid needed to fix problem)
SO besides having the dealer do a complete flush,TCM update, here are a few things I have done to improve the shifting on the 42RLE.
Check fluid level when hot in Neutral on level surface. (was at full line by dealer)
ADD: Two bottles of Lubgrad red: http://www.lubegard.com/~/C-112/LUBEGARD+Automatic+Transmission+Fluid+Protectant
This is a quality friction modifier, and after adding the 2 bottles, (slightly above full now) the 42RLE seems to have improved in it's shifting characteristics.
Cleaned the throttle body & IAC (idle air control) allowing for more responsive rpm control, and keep an eye on your rpm to see as you are stopping that the low rpm was dropping to 550 rpm, like mine was, which may be part of the whole problem. Replacing the IAC may be a good idea and cleaning the ports well, may also assist in maintaining a better rpm.
 
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Alejandro

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I cleaned, and replaced the TPS (Throttle Position Sensor). My Jeep has been working perfect ever since. No shifting problems, RPM jumps or slumps or a sense of discomfort at stops. I recommend this as a solution.
 

MikeHype

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My 2005 Lib doesn't do this, but my Mother-in-Law's 2007 sure does.
From a stop, it just seems to require more effort to push the gas. When it finally goes you get a lurch. I've been telling her to take it in. Good to know there are others.
 

rockymountain

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the 07 has drive by wire. electronic throttle.
you have an actual physical cable that moves the throttle.

chrysler drive by wire vehicles make me sick. especially the jeeps. Can't stand them and I'll never buy one unless they make 'em better.
 

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