After about 30 minutes of drive time, I start to have surging boost, where it will go from 10 - 15 lbs down to 4-5, and then if I step into a little harder, it will pop right back up to where it was. I suspect that I may have an exhaust leak or something and think maybe the manifold gets hot enough after a while to leak at the turbo. This is simply my best guess. Any suggestions?


BTW, what is this adjustable boost elbow that everyone keeps talking about, where does it go and what does it do?

 

what are your rpms doing when you are loosing boost?

 

thats also a symptom of apps going bad, are you getting code , if not then is more than likely that. had exact same problem and was apps

 

Not going to fix you problem - check for codes.

The boost elbow allows your turbo to build more boost (output obviously) before the wastegate opens. And its more desirable (in my mind anyway) than disabling the wastegate.

 

no codes, I have another apps at home, from chasing earlier problems that turned out to indeed be the vp44 and injectors, maybe in a couple of weeks, I will try swapping that apps back to the old one. Shouldn't the apps spark a code too? like 0121?

 

could be the boost sensor mine did the same thing. on rough roads it would fluctuate and on smooth roads i had no boost
bought the boost (map) sensor from the local stealership for $98 bucks