# Rough idle, rough acceleration - No MIL codes.



## obermd (Mar 3, 2012)

Did you actually replace the PCV valve and cover? P0171 is frequently the PCV valve and cover.


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## Merc6 (Jun 8, 2013)

@ 106K you could have gotten that valve under power train assuming your car had more than 7 miles on it when you purchased it...


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## josh2012eco (Oct 6, 2014)

7k miles... ^^^^^^


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## Merc6 (Jun 8, 2013)

The period starts when the new car is titled. Say the car sat up and was driven 44 miles before someone go it, the warranty would say 36,044 B2B 100,044 Power train and like 80,044 emissions in the system. My 03 Mazda 6 was purchased new with 170 miles on it.


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## hificruzer226 (Mar 27, 2013)

merc6 said:


> the period starts when the new car is titled. Say the car sat up and was driven 44 miles before someone go it, the warranty would say 36,044 b2b 100,044 power train and like 80,044 emissions in the system. My 03 mazda 6 was purchased new with 170 miles on it.


si cho es corec mi amigo!


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## cufarmer (Oct 16, 2014)

Yes, shiny new valve cover. Car had 9 miles on it at purchase. After changing valve cover, no more codes. But the sputtering and no acceleration continues. It's rough enough to trip the "service stabilitrak/traction control" message. I might pull negative cable and post results.


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## Imaperson (Apr 18, 2013)

My car has this exact problem at 34k. I am tuned however. Misfires like no other between 3 and 4k at part throttle. Once it's over 4k it'll go just fine. I've been able to get it to set a p0300 pending but no cel. Usually the computer will refuse to lock the torque converter and set the traction and stability control warning lights on after I drive it trying to get it to set a code. 
I've changed plugs, cleaned map and maf, everything short of replacing the coil pack. So it's on the suspect list until I can test or replace it.


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## cufarmer (Oct 16, 2014)

Thanks everyone. Right, Imaperson. Any idea how to test this coil pack?


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## obermd (Mar 3, 2012)

I don't know how to test it but we had one member having rough idle and when they pulled their coil pack they found one of the coils was starting to corrode.


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## Imaperson (Apr 18, 2013)

No corrosion that I can see here. Though if I knew how this thing was wired up, could check primary and secondary winding resistance in the coil. See if there's a spec, or if they are at least consistent across the pack.


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## Imaperson (Apr 18, 2013)

Just as a follow up here, I wound up changing the plugs to NGK BKR7E plugs. All of the stumble and surging I was having is completely gone. Will see how it holds up over time, But very pleased so far.


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## cufarmer (Oct 16, 2014)

I am still working on the problem with the ignition coil. I have swapped out plugs but the number 3 cylinder consistently misses.


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## neirfin (Oct 18, 2012)

cufarmer said:


> I am still working on the problem with the ignition coil. I have swapped out plugs but the number 3 cylinder consistently misses.


did you make sure the springs inside the coil boots aren't caught up on the rubber? when I changed my plugs I noticed 2 of them were caught on the boot, may have been keeping them from making solid contact with the plugs. something to check for anyways.


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## gannman2000 (Jan 28, 2019)

I have a 2014 Cruze, 1.4L Eco and I have the exact same problem. 
Idle is smooth, but very poor and jerky acceleration, especially between 2 and 3k on the tach. Also noticing an engine/oil/exhaust smell when stopped. 
If I manually down shift and get the revs high, then I have some acceleration power, but it is still weak. 
I also have the cylinder 3 misfire, according to the computer, but no codes. 
I replaced the #3 plug spring, plug boot, and spark plug, but I still have the problem.
I am going to replace the coil pack next, as the only visual clue I have seen was some dirtiness on the top of the original #3 plug spring, and inside the #3 coil pack barrel. 
Might be #3 fuel injector, so that is also on my hit list.


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## Singerro (7 mo ago)

gannman2000 said:


> I have a 2014 Cruze, 1.4L Eco and I have the exact same problem.
> Idle is smooth, but very poor and jerky acceleration, especially between 2 and 3k on the tach. Also noticing an engine/oil/exhaust smell when stopped.
> If I manually down shift and get the revs high, then I have some acceleration power, but it is still weak.
> I also have the cylinder 3 misfire, according to the computer, but no codes.
> ...


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## Singerro (7 mo ago)

gannman2000 said:


> I have a 2014 Cruze, 1.4L Eco and I have the exact same problem.
> Idle is smooth, but very poor and jerky acceleration, especially between 2 and 3k on the tach. Also noticing an engine/oil/exhaust smell when stopped.
> If I manually down shift and get the revs high, then I have some acceleration power, but it is still weak.
> I also have the cylinder 3 misfire, according to the computer, but no codes.
> ...


Did you ever end up finding out what the problem was?


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## PAChevyCruze (May 29, 2016)

Singerro said:


> Did you ever end up finding out what the problem was?


Sounds like a bad coil pack. Went through 2 of them until I got the ZZP one. Problem fixed.


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