One of the common symptoms of no boost is that large rubber boot you will in the middle of the hood leading into the throttle plate assembly comes loose. But that does throw codes, it did for me.

 

And if not a hose, could be a diverter valve that is stuck open (or closed) that is not allowing boost to build.

 

many miles and years of service - could be either of the items noted above...

Check 'em out.


Good luck!

 

Thanks everybody. Will aim to look at these this week.

I did a quick check of the intake hose and it does appear/feel to be tight. Will give it a more thorough check though.

the diverter valve is a different part than a wastegate?

 

I have had this same issue, it is pretty rare for me and appears to happen more on cold mornings when first starting up. Turning off and on fixes it Everytime. I did have an error message pop at one point that was something to do with engine airflow, pics posted below. My tech couldn’t find any issue and the warnings haven’t come back since. Let me know if you find a solution!