GM turbo upgrade was installed a couple of years ago.
Last winter I had a problem with boost.
It's back and it has something to do with cold weather and right hand turns.
It worked fine all spring, summer and fall.

I warm the car up.
I leave my driveway, proceed to a stop sign and make a right turn.
I can only get 5 psi. I reach another stop sign and stop.
I turn left. It will boost to 21 psi.
I make another left and it still works with or without having to stop.
I come to another light. I turn right. 5psi. Auto shifts to second and still only 5 psi. It will give me the full range of rpm but no boost.
If I back out of it and nail it, it will give me full boost.

This is now happening every day and it only started when it got cold.
There is never a check engine light.

 

I'm not Mr. Goodwrench,... but when mine was acting like that, they replaced the lower sensor and installed a bracket to hold the cold side pipe from moving. This eliminated the rub when the engine moves. The dealer made it. Thats what I would do, good luck I know the 5lb boost thing cause I drove it while we were waiting for the new sensor to come in. Very slowly

 

^^^^think you hit the nail on the head mr goodwrench

 

Try adjusting lower TMAP for clearance and TTR solid engine mount. Helped me.

 

Everybody has issues with rubbing. SS that is awesome that your dealer did that! In my case I flipped the T-Map 180* when putting on the cold pipe. works like a charm.