# Trouble code P0171 and P0496 (Rough idle/engine cough)



## Josephb10001 (Dec 4, 2018)

Hello, everyone, just had a CEL come on my 2012 Chevy Cruze 1.4L Turbo. Used a code reader and it said P0171 and P0496 which I guess reads to lean and and issue with the EVAP system. After reading some posts on similar issues (everyone here seems to be a great resource and wealth of knowledge). I think the issue is either the PCV valve or the Purge Valve Solinoid. However I was unable to determine in the PCV valve was pulling in air. So I’m not sure how make sure it’s one or the other. 

So the symptoms im having is a rough idle and what I could describe as almost an engine cough. While at idle it will start idling even harder and the rpms drop (rather than really not moving at all), and go up then back down and I can feel it just kind of puttering. Does that for maybe 10-15 seconds then idle will level out again. Not sure if this is helpful but any advise would be appreciated! Just don’t want to buy the wrong part... 

Thanks!


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## Robby (Mar 1, 2013)

Remove coil cover to see burst disc cover (often called PCV). With engine running, a burst disc will suck air through a vent hole in the front of the disc cover, located towards the left (or drivers side in the US and others) side of the cover.

Just put your fingertip against the vent hole to cover the leak......noise will stop, engine will smooth out if a failure has occurred. 
If the burst disc did fail, there is a better than average chance the check valve in the intake manifold has disintegrated and the uncontrolled vacuum is what caused the burst disc to rupture.

Photos are posted on this forum for how to check the manifold.

Rob


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