# Bad PCV or? vacuum leak



## justAverage (Nov 9, 2012)

2009 MKV GTI 2.0t TSI 95k miles. few days ago car starts getting irregular idle and cuts in boost/acceleration. CEL had come on because of it so i took it to my dealer since they offer free diagnostics. they run it and tell me my PCV is going bad along with my DV (older diaphragm revision) so i buy the newest revision PCV and a rev-d DV thinking problems will be solved. come home and install only to find the leak still exists. try the oil cap test while engine is running and its hard to remove and engine wants to stall out right away once its off. same with the dipstick. next check i try the MAF thinking it may be a culprit. unplug the MAF while engine is running and the idle smooths out and sounds great. plug it back in and goes back to irregular idle. so i take the MAF out and clean it and try again, nothing. try a new MAF and still same issue. checked all my vacuum hoses and fittings made sure they are all connected and sealed up and it all checks out. is there anything else im not thinking of? only thing that comes to mind is maybe i somehow bought a faulty PCV? or? need some advice please! :banghead:


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## justAverage (Nov 9, 2012)

Bump 

I am getting this error code, P2279 - Leak in Air Intake System.

Any recommendations?

Here is what Ross-Tech says about it:

18711/P2279/008825 - Leak in Air Intake System

Possible Symptoms
-Malfunction Indicator Lamp (MIL) active

Possible Causes
-Vacuum Leak
-Intake Manifold Runner Position out of Specification
-Faulty Positive Crankcase Ventilation (PCV) System or Heating Element (N79)

Possible Solutions
-Check Intake System for Leaks
-Check Intake Manifold Runner
-Check (PCV) System and / or Heating Element if applicable

Special Notes
-When found in the NAR 2.0T (BPY) check RVUTB: 01-09-03 or 2018919 for updated Crankcase Breather Valve
-If the breather valve is faulty, full engine vacuum is typically found when removing the oil cap at idle.

http://wiki.ross-tech.com/wiki/index...1/P2279/008825



IG: @justAverageMKV


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## kbad (May 26, 2007)

hey man .. you get this sorted out yet? .. a year too late, but for s&g another place to check is the brake booster vacuum hose - it tends to have hairline cracks along hose and/or at connecting ends .. good luck!


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## alanbrito (Aug 12, 2006)

I've been having the same issues, I got another thread going. Between my mechanic and I, we have determined it is one of the following:


bad PCV valve/hose: even though dealer installed a new PCV (apparently not the right part number for a FWD GLI, rather for a transversally mounted FSI Quattro configuration), the car does seem to improve/make boost if I remove the front breather hose or plug it and then put it back in. Not sure what is causing what at the moment. 
vacuum leak somewhere else: the break line booster seems a candidate
carbon buildup: might be worth looking into an intake manifold cleanup


once I get sorted out I will update my post as well, as it is nice to come here and actually find threads with issues resolved rather than just open ended, year long attempts at fixing such issues.


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