P0172 and hissing sound

[JB-GTi]

Hello,

I have a 2008 GTi automatic, 3 days ago I began to hear a hissing sound at 2500 RPM, also I felt the car doesn't accelerate as well as before. Yesterday, the engine light went on, and the scanner is showing a P0172 code (System too rich bank 1). What could be the problem?
The car has 100,000 miles, we recently changed the PCV valve and the Turbo Diverter Valve.

 

[BurgerGuy]

See here:

• http://wiki.ross-tech.com/wiki/index.php/16556/P0172/000370
• This one may be your best bet: https://www.golfmkv.com/forums/index.php?threads/p0172-system-runs-to-rich.173039/

 

[JB-GTi]

See here:

• http://wiki.ross-tech.com/wiki/index.php/16556/P0172/000370
• This one may be your best bet: https://www.golfmkv.com/forums/index.php?threads/p0172-system-runs-to-rich.173039/

Thanks, 6 months ago I replaced the Diverter and PCV valves due to other error codes (P0299). So, I think it is too soon for them to be bad again, I'm going to replace the air filter and clean the MAF and see if that helps.

 

[BurgerGuy]

It's all plastic where the front PCV valve mounts to the valve cover so if you overtightened something that could be part of your problem. The only way to know for sure where the leak is coming from would be to smoke test the system at a shop. Better to do that than throw parts at the car, but a filter and cleaning your MAF are good to do regardless.