# Engine skipping, bucking



## IndyDiesel (May 24, 2015)

Draining filter makes sense, I would try that first, if that doesn't work might make sense to change fuel filter. But what if you have more water in fuel still?


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## 2014Oilburner (Feb 1, 2015)

Did you get the "water in fuel " message....I have a few times and drained my fuel filter a few times..one time I got quite a bit of water...like a cup full sitting in the bottom of the glass container that I drained the fuel in....another time I drained the fuel filter and I really couldn't see much water at all dispite the "water in fuel " message...but it did shut off the message. Had the water in fuel message a third time and did nothing but changed where I was buying diesel from and haven't seen the water in fuel message for months now...anyways...never did the car buck or anything and ran perfect even before I drained what looked like a full cup of water from the fuel filter...just my experience with some water in the fuel.


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## Barefeet (Jan 1, 2014)

Thanks, It did get worse today just before the low fuel light came on. There was no message or CEL.
I'll post tomorrow after the service dept checks it out.


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## diesel (Jun 8, 2013)

One more idea - Check the intercooler piping. It might be starting to crack.

http://www.cruzetalk.com/forum/64-g...sion/176233-engine-reduced-power-smoking.html

http://www.cruzetalk.com/forum/64-g...mmon-issues-fixes-2014-2015-cruze-diesel.html


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## hbilow (Sep 17, 2016)

I have noticed mine doing some strange things like bucking and coughing at low speeds, right before a DPF Regen. Once the Regen is complete it runs fine again.


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## Barefeet (Jan 1, 2014)

hbilow said:


> I have noticed mine doing some strange things like bucking and coughing at low speeds, right before a DPF Regen. Once the Regen is complete it runs fine again.


You may be right, thats when it happened. 
The service man drained the fuel filter and found little to no water.
The car seems to be running fine now.


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## jblackburn (Apr 14, 2012)

Makes me wonder if it's sensor related. Usually (well, if not water), hiccuping acceleration is some sort of air metering problem.

Have you seen the thread about cleaning the MAP sensor in the diesel?

http://www.cruzetalk.com/forum/201-...-mileage-loss-fix-clean-map-sensor-again.html


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## Snipesy (Dec 7, 2015)

Could also just be air getting in the line somehow.

If it's only occurring at low fuel, then it's probably something to do with the lift pump or sump in the tank itself.

Otherwise... Have fun hunting...


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## CruzeDan (May 17, 2015)

hbilow said:


> I have noticed mine doing some strange things like bucking and coughing at low speeds, right before a DPF Regen. Once the Regen is complete it runs fine again.


Mine does this at certain speeds while at certain times during regen or before a regen too. Happened real bad a few times. Car doesn't have any issues, nor has ever had any water in the fuel. Every time it is drained nothing comes out. I think it's normal honestly because it happens at such rare and narrow times and RPM/speeds.


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## IndyDiesel (May 24, 2015)

Probably not related at all but a friendly reminder, might check the five wire clamps on the air tube and make sure they are snug, with the diesel vibrations they can work loose pretty easily.


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## diesel (Jun 8, 2013)

I've never had any issues like this before a regen.


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## MRO1791 (Sep 2, 2016)

diesel said:


> I've never had any issues like this before a regen.


Neither have I for either CTD.... However it's normal for a bit of unstable throttle on my Cummins TD during a Regen. 

Sent from my Moto G (4) using Tapatalk


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## Snipesy (Dec 7, 2015)

I've never seen such issues like 'coughing' during a regen. I've only seen those issues when it just started from -20F or the one time I got the throttle valve stuck :blush:. It also does a little bit of a... skip... When the ecm does a sort of reset after finishing a test. Which might be what you guys are hearing. But it's very subtle and something you could easily miss unless you have a good ear.


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## diesel (Jun 8, 2013)

Snipesy said:


> It also does a little bit of a... skip... When the ecm does a sort of reset after finishing a test. Which might be what you guys are hearing. But it's very subtle and something you could easily miss unless you have a good ear.


Is this by any chance at 12 MPH after starting out for the first time, or are you describing something else?


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## Cruzator (Dec 31, 2014)

I have had my randomly "buck" a few times around 20-25 MPH at very light throttle. It will buck twice and then stop. It hasn't done it for a few month now. Sometimes it would do it every few day, but usually less than once a week. I aways assumed the computer was doing some sort of test, but I have no idea. If I step down on the throttle a little, it quits. This isn't when it is in regen or getting ready to regen. Just my two cents worth.


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## diesel (Jun 8, 2013)

Cruzator said:


> I have had my randomly "buck" a few times around 20-25 MPH at very light throttle. It will buck twice and then stop. It hasn't done it for a few month now. Sometimes it would do it every few day, but usually less than once a week. I aways assumed the computer was doing some sort of test, but I have no idea. If I step down on the throttle a little, it quits. This isn't when it is in regen or getting ready to regen. Just my two cents worth.


That sounds to me like the natural characteristics of the transmission. Mine has done that since new. It's sort of like harsh shifting into or out of a couple gears under very particular circumstances.


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## Cruzator (Dec 31, 2014)

I have noticed a few quirks with the transmission, but this is the engine. I've even put it in manual mode before while it's doing it. No change..


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## diesel (Jun 8, 2013)

Cruzator said:


> I have noticed a few quirks with the transmission, but this is the engine. I've even put it in manual mode before while it's doing it. No change..


I've never noticed anything like that in manual mode.


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## Barefeet (Jan 1, 2014)

As a follow up on this post. The skipping and bucking is definitely caused by the regen. I think it is worse since the reprogram recall. It is only noticeable at speeds below 50. I have generally been pleased with the reprogram, because I can now go 550 to 1100 miles between regens. instead of 150 miles, however, the mpg may be a little lower.
It did post a CEL this last time P2425 Exhaust gas recirculation bypass valve?? I cleared the code.


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## MRO1791 (Sep 2, 2016)

Barefeet said:


> As a follow up on this post. The skipping and bucking is definitely caused by the regen. I think it is worse since the reprogram recall. It is only noticeable at speeds below 50. I have generally been pleased with the reprogram, because I can now go 550 to 1100 miles between regens. instead of 150 miles, however, the mpg may be a little lower.
> It did post a CEL this last time P2425 Exhaust gas recirculation bypass valve?? I cleared the code.


A EGR sticking / binding.. then a Regen... I could see some rough Engine behavior from that. I'd be checking that EGR valve.

Sent from my Moto G (4) using Tapatalk


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## diesel (Jun 8, 2013)

Barefeet said:


> As a follow up on this post. The skipping and bucking is definitely caused by the regen. I think it is worse since the reprogram recall. It is only noticeable at speeds below 50. I have generally been pleased with the reprogram, because I can now go 550 to 1100 miles between regens. instead of 150 miles, however, the mpg may be a little lower.
> It did post a CEL this last time P2425 Exhaust gas recirculation bypass valve?? I cleared the code.


Seems like you have a fairly unique situation. I would imagine there's a clue in the P2425?


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## starspangled6.0 (Apr 16, 2016)

I see a prime candidate for a delete and tune


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## Blasirl (Mar 31, 2015)

I see you have decided that it was the regen and not the water, but if it were the water, would either of these work?

Diesel Water Remover

Tank Snake


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## Barefeet (Jan 1, 2014)

I'm not sure, I'll have to look for the CRC product. I don't think I would put the "snake" in my tank.




Blasirl said:


> I see you have decided that it was the regen and not the water, but if it were the water, would either of these work?
> 
> Diesel Water Remover
> 
> Tank Snake


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## diesel (Jun 8, 2013)

As far as the tank snake goes, it sounds interesting, but I would think the fuel filter would do all that.


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## sparkola (Jun 9, 2014)

My 2014 does the exact same thing during a regen. 70000 miles. It's less noticeable at highway speeds but will cause me to glance at the instant fuel economy meter to verify that I'm getting 99 mpg during a deceleration with the top led not lighting up.


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## Barefeet (Jan 1, 2014)

sparkola said:


> My 2014 does the exact same thing during a regen. 70000 miles. It's less noticeable at highway speeds but will cause me to glance at the instant fuel economy meter to verify that I'm getting 99 mpg during a deceleration with the top led not lighting up.


Mine still does it, however I just keep the RPM up by downshifting or driving over 50 and it is not a problem. I suspect that my service department would be glad to replace the EGR, but I'm not anxious to spend the money.


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## EricSmit (Dec 21, 2016)

Did you get an answer from your service department?


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