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Drivetrain hesitation and bucking

94K views 26 replies 13 participants last post by  Ignatz 
#1 · (Edited by Moderator)
Good evening, I have a 2014 Jeep Patriot with approx 60k miles on it.

Recently, the vehicle started to hesitate and buck when accelerating, when coasting, and reapplying the gas and especially on hills. I took it to the dealer where it has been for the past month with no resolution. They can duplicate the problem and have done a driveability upgrade and replaced the transmission valve body. They also lubed and adjusted the transmission shift cable.

The bucking incidents happen very frequently and feel like several quick studders between shifting. Long story short I'm frustrated without having a vehicle for a month, the investment of several hundred dollars in repairs, and no resolution. Has anyone experienced something similar or what might be a cause of this? There are no stored codes or mil on.

Thank you
 
#3 ·
This may sound too simple, but many members have solved bucking/jerking/hesitating problems by changing the plugs. They are on the maint schedule to change at 30k miles.
x2

That's what I'd check next, if it hasn't already been done.
 
#5 ·
i had exactly same issue from day 1. it got worse and worse then instead of the bucking it would almost shut off the come back on really fast- like a long miss.

the etc light would flash and if you weren't looking for it you would miss it. then one day it stayed on for a few minutes. then went off.

long story short, i had a bad throttle body. they replaced under my lifetime added care plus less the 100$ deductible at 54,000 miles. i still get the once in a blue moon studder and expect a new throttle body in another 50k miles.... lol....chinese junk parts...

IF yours is not covered by any warranty, it may not be at 60k miles, i recommend pulling the codes- did they pull codes at dealer?- and confirm throttle body.


if it is the throttle body and not covered, i'd buy the one from rock auto for $140 which has a lifetime warranty as i recall and the part description specifically mentions it having a revided design to eliminate the OEM failure flaw....i would NOT pay over $500 for the dealer to replace with another cheap oem part that will fail in another 50k miles. I'd buy the rock auto one.

remember, mine did the same it appears since about new and slowly got worse. so maybe yours hasn't set the code yet.....

like other said, replace plugs with OEM plugs only. check air filter. replace as needed. easy and cheap.

if it still does it, i'd bet your throttle body is going out and from what i read, you can't clean it...must replace...
 
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#6 ·
$132.99


More Information for DORMAN 977025

The Electronic Throttle Body Assembly frequently requires replacement due to internal electronic sensor failure and excessive wear and tear. Dorman's OE FIX solution provides a redesigned electronic board, which features a new Hall Effect Sensor for increased reliability and a longer service life. Sold as a complete unit, Dorman's Throttle Body features a butterfly valve which is electronically controlled by the Engine Control Unit to precisely open and close to regulate the fuel/air mixture. Since this part is essential to the operation of your vehicles engine, quality tests on this part include on-vehicle testing and corrosion resistance testing to ensure this part conforms to product standards for durability and performance.

Aluminum casting construction for an exact fit, performance match and corrosion resistance
Exact fit for bolt-on and plug-in installation
Direct replacement restores proper engine function
The Electronic Throttle Body Assembly maintains the correct volume of air flow into the engine
 
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#7 ·
Terminology can be confusing here. I'll share my problem and how I solved it.

First, go for the cheap fix first. Replace the plugs. You're talking <$20 and it might be all you need.

If that doesn't do it, may I ask the condition of your tires? Mine was stuttering on hills. Not usually from a dead stop, but during acceleration after it was already moving, like getting on an entrance ramp or coming to a hill where it needed more power. It was like the whole engine quite for an RPM or two, then it would smooth out. If it was a long hill it might happen again. At the time I had inconsistent tires -- one axle had fairly new tires, the other well-worn tires, and I think they were undersized. My guess (only a guess) is that the tires moving at different speeds was confusing the computer.

Please check back when you've got things figured out.

PS, at 230,000 miles I'm still on my original throttle body so if I were you, I'd be reluctant to spend that kind of money on speculation. I don't burn anything special for fuel; always regular, usually Irving or whatever Cumberland Farms is selling (Citgo I think).
 
#8 ·
I actually saw this posters thread when i was having the issue at first. coincidentally, my issue started the very next time i drove my jeep after i rotated tires. So i thought the above was the cause. In my case, replacing the throttle body resolved things.

unless replacing the throttle body leads to another process that resets something associated with tires being out if spec to one another. i don't know. i just know after throttle body it hasn't happened again....and i have rotated the same tires a time or 2 since..
 
#9 ·
Throttle bodies can be cleaned, done mine twice.

There's two prevalent failure modes on a TB. Carbon build-up and stepper motor failure.

Carbon build-up on the throttle bore causes the throttle blade to stick, giving noticeable throttle response issues like jerking and bucking since the stepper motor cannot smoothly overcome the resistance of the blade interference. Enough build-up can cause stepper motor failure as well as it has to work harder.

Stepper motor failure or impending failure will also cause ETC and driveablity issues albeit at significantly more cost since this requires the replacement of the complete TB assembly.

There can also be electrical causes found in the wiring harness, ground points and relay/fuse boxes.

If one has the DIY ability, the cheaper option should be explored first. I would use the new CRC intake valve cleaner instead of TB cleaner. It has the better formula to dissolve the carbon more effectively and the procedure can be done from topside of the engine compartment. If there is no change in driveability then further troubleshooting will be required.
 
#10 · (Edited)
Over several decades, I have had several engine problems with symptoms similar to the OP with no codes thrown. In all cases, it took a very experienced mechanic with a "scope type" diagnostic scanner to diagnose the problem. In one case, I had a bad plug wire that was mis-firing intermittently. Another time it was a bad throttle speed sensor that sent bad signals to the tranny, causing symptoms like it was "slipping". No codes were ever thrown.

Ask your dealer if they have tried any testing (scope) beyond a regular code scanner.

Here's an example of a scope type diagnostic tool: skip ahead to see it in action.
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#11 ·
Thank you all for your responses. I changed the plugs and after road testing the problem has totally resolved. The plugs didn't actually look that bad but a definite difference and total resolution of the problem. I'm happy that this is resolved but pretty frustrated that after 2.5 weeks in the dealership and $400 in repair bills that the dealer couldn't have resolved this in the 15 minutes and $20 that I invested in my driveway. Thank you all again... this was very helpful
 
#13 ·
i have a 2012 with CVT with 80K+ miles and this happens when i either gas it to pick up speed on highway or up hill at or just under 2500rpm. thought maybe misfire but no codes. i hope it is just the spark plugs and then i ll just have to apologize to my CVT for bad mouthing so much.
 
#14 ·
Its not your tranny. If it was slipping it would have died almost immediately.

Plugs are the cheapest possible route. Start there.

If that doesn't do it, what are your tires like? I've posted a couple times about having a problem similar to yours and concluded it was due to different tires on different axles. In my case it was nice new ones on front and really worn undersized on the rear. I think the different tire sizes turning at different speeds confused the computer, especially when its being asked to make a change, like starting to climb a hill. Like you, my problem was between 2000 and 3000 rpms, and it wasn't heavy acceleration that did it, just a little stronger than usual -- like you say a hill when the CVT makes a change in ratio, or leaving the toll gate and going from 30 to 60 mph.

So if your rubber is junk, that might be your problem. If your tires are consistently good and not odd-sized maybe your computer is getting bad data. GIGO.
 
#15 ·
it was the spark plugs. replaced all 4 and no issue. be nice if CEL came up. its like they want you to bring it into the shop. who ever did the spark plugs prior to me purchasing had a little too much fun with the dielectric grease. had dig some out of the coil with a screw driver.
 
#17 ·
Spark Plugs

I have a 2013 Patriot with just over 100,000mi and the same hesitation upon acceleration from a stop or roll or on a hill. I also feared the worst, CVT replacement. However I changed the plugs and so far the problem seems to be fixed. Thank you so much for posting such a simple repair. It sounds like you've helped a lot of people!
Thanks again and God Bless,
Nick
 
#18 ·
I have a 2013 Patriot with just over 100,000mi and the same hesitation upon acceleration from a stop or roll or on a hill. I also feared the worst, CVT replacement. However I changed the plugs and so far the problem seems to be fixed. Thank you so much for posting such a simple repair. It sounds like you've helped a lot of people!
Thanks again and God Bless,
Nick
Welcome, Nick52! I'm glad the site has been helpful for you. Please visit the newbie threads and introduce yourself to the gang! Tell us about your Patriot. Engine, drivetrain, color, mods, etc.
 
#19 ·
DaveR

The bucking problem on my 2013 Jeep Patriot started at about 120K miles (after the transmission had already been replaced at 99K). First noticed it going up hills, then it became continuous - but only after the car had been running for 1-2 hours of driving. One AAA mechanic first told me he saw "flames" shooting out of the manifold cover, but then later said they couldn't get the car to repeat the bucking. Va. Beach mechanic changed spark plugs but said he couldn't find any code issues. My mechanic finally found not one but two fried catalytic converters and replaced both. Problem solved... for a while. Now it's starting back up again, and I'm getting frustrated that everyone who has looked at it talks about codes and not what's going wrong with the car. Plugs have been replaced, wires checked, catalytic converter tested. Do you think a new CVT would solve it? Any clues in the fact that it starts when the motor is hot from 2+ hours of driving, or that it starts when starting driving up hills, then spreads to driving up hill, down hill or on level ground?
 
#26 ·
DaveR

The bucking problem on my 2013 Jeep Patriot started at about 120K miles (after the transmission had already been replaced at 99K). First noticed it going up hills, then it became continuous - but only after the car had been running for 1-2 hours of driving. One AAA mechanic first told me he saw "flames" shooting out of the manifold cover, but then later said they couldn't get the car to repeat the bucking. Va. Beach mechanic changed spark plugs but said he couldn't find any code issues. My mechanic finally found not one but two fried catalytic converters and replaced both. Problem solved... for a while. Now it's starting back up again, and I'm getting frustrated that everyone who has looked at it talks about codes and not what's going wrong with the car. Plugs have been replaced, wires checked, catalytic converter tested. Do you think a new CVT would solve it? Any clues in the fact that it starts when the motor is hot from 2+ hours of driving, or that it starts when starting driving up hills, then spreads to driving up hill, down hill or on level ground?
I know Im a little late to the party but.... My 2015 Patriot with 115k on the clock Is having these exact symptoms. The only difference is, mine is a manual. I'm really curious if eventually you found the culprit. If it was the trans, plugs, coil packs, or what-have-you. Mine has done it once under load going uphill, once on flat casually accelerating to 40, and once just cruising in fifth. My tires are undersize by a hair, but I'm starting with plugs tomorrow and the game will really begin..
 
#20 ·
Unless your tranny is making noises (hum, whine, etc) it probably isn't the problem. A new transmission is a very expensive guess.

Don't confuse bucking with slipping. If its slipping you'll feel the engine race disproportionately to what your asking of it and the resulting speed and then it will catch again, but its a fairly smooth effect. Particularly noticeable at lower speeds, but it can happen at any speed.

Did you read my posts above about tires? Your symptoms seem similar.

One more guess: coil packs?
 
#21 ·
#22 ·
Good evening, I have a 2014 Jeep Patriot with approx 60k miles on it. Recently the vehicle started to hesitate and buck when accelerating, when coasting and reapplying the gas and especially on hills. I took it to the dealer where it has been for the past month with no resolution. They can duplicate the problem and have done a driveability upgrade and replaced the transmission valve body. They also lubed and adjusted the transmission shift cable. The bucking incidents happen very frequently and feel like several quick studder between shifting. Long story short I'm frustrated without having no vehicle for a month, the investment of several hundred dollars in repairs and no resolution. Has anyone experienced something similar or what might be a cause of this? There are no stored codes or mil on.
Thank you
Yep You guys ROCK I had both these issues bucking and shaking and the plugs did the trick for $100 and I felt like my Jeep was falling apart so thank you very much for all the tips!!!!
 
#24 ·
Good evening, I have a 2014 Jeep Patriot with approx 60k miles on it. Recently the vehicle started to hesitate and buck when accelerating, when coasting and reapplying the gas and especially on hills. I took it to the dealer where it has been for the past month with no resolution. They can duplicate the problem and have done a driveability upgrade and replaced the transmission valve body. They also lubed and adjusted the transmission shift cable. The bucking incidents happen very frequently and feel like several quick studder between shifting. Long story short I'm frustrated without having no vehicle for a month, the investment of several hundred dollars in repairs and no resolution. Has anyone experienced something similar or what might be a cause of this? There are no stored codes or mil on.
Thank you
Thank You! My Jeep Patriot has just turned 70,000 miles and started the same issues. I replaced the Spark Plugs with AutoLite Plugs and got a can of Throttle Body Cleaner. Replaced the plugs and cleaned the Throttle Body. The Jeep Patriot runs like new again. Thank you everyone for your responses and help. I just wanted to let you know that you also helped me. I did the labor myself so it cost me a total of $30 and I am getting a rebate on the plugs too. God Bless and have a great day!
 
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