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Just got your e-mail. Thanks for that. Figured I'd explain here for anyone else's benefit.

The check valve in the intake manifold tends to leak if it does last that long, which effectively creates a similar issue. The P0299 is an underboost code. It means that for a given engine load, which should be spinning the exhaust turbine, the engine is not seeing the expected boost pressure. This can have a number of root causes. The intake manifold check valve leaking is one of them, which leaks boost. External boost leaks will also cause this. An excessively large crack in the wastegate housing of the turbo could also contribute to it. Note that these are all contributing factors and may not be sole individual factors. A crack in the wastegate housing, which is extremely common, may contribute to a boost leak but may not be enough on its own to cause an underboost condition unless there are other contributing factors, until it gets big enough.

The factory allows some variance/tolerance for these issues to exist without throwing the code. I would start with the intake manifold check valve, then start looking for boost leaks. Here's a video I made on this topic:

https://www.youtube.com/watch?v=heQYgmcGnHI&t=

There is a little rubber vacuum hose on the passenger side underneath the intake manifold that often cracks/tears and produces a substantial boost leak. Be sure to check that as well.

Only after you've addressed all potential boost leak points would I consider replacing the turbo.
 

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Thanks Xtreme, just ordered your PCV kit. Regarding the vacuum hose underneath intake manifold, is that the small hose that is attached the the larger PCV hose that runs from the intake to the Turbo?

I took off the large hose at the check valve and could blow air through it, but it "mostly" was sealed when I tried to suck air through it (i.e. from turbo to intake manifold).
Yeah it's a small rubber hose that connects into a plastic one that runs next to the large corrugated one.

You shouldn't be able to suck air back through at all. It should be completely sealed.
 
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