On a recent trip I determined I wasn't getting boost. Especially horrible becusse I was towing a trailer in the mountains!
I had no codes so it was a nightmare.
I came across a YouTube video showing the leaky VC vacuum reservoir and sure enough mine failed the test.
I was already planning to replace VC this summer so I ordered a replacement sent to where I was 800 miles from home. Fortunately I brought enough tools to take care of the job. Sadly didn't bring my torque wrench so had to use my torque adapter which isn't automatic had to read the digits and with ≈26 bolts that was tedious took about 4 rounds or > 100 tightening episodes.
With no code showing I did more searching and boost leak and boost solenoid and map sensor were other candidates for a problem so with FCP return policy I bought those two parts also.
When I got the VC off made simple work to get to the boost solenoid. I put a piece of vacuum hose on it and sucked with my mouth plugging the other fitting and was surprised I could suck though. I tried both ways and air came though either direction.
I did the same test on the new one and it held vacuum. Eventually I picked up a vacuum/pressure tester and confirmed the results.
The loss of boost was instant. I did a few wot runs to "let's say triple digits", and no problems then stopped for gas and getting on the freeway I noticed my steady state mileage was terrible. Under 20 when I'm used to 24.
I thought maybe I got some bad gas and used injector cleaner on a few fill ups with some improvement but I had to use sport mode and M/S in the hills or getting to speed.
First drive with the new parts had instant satisfaction. Measured sub 7 second 0-62 but more importantly butt Dyno said things were back to normal.
Then the fun:
GPS said 28 minutes on back curvy roads to town out in the country. Made it in under 20!
https://www.icloud.com/sharedalbum/#B0Z5yeZFhU8G6Y
Some pov video of killing my mpg!
If I drove like a "fossil" as wife would say, I could get 21 even in the hills and more than 1000' of elevation change, but post fix and "hammer down" I pulled that doen to 14.
I didn't end up using the map sensor so I need to return that.
I didn't have my smoke machine with to do a smoke test on the intake but if there's a leak it's minimal. I will do that though. With the leak I had in the boost solenoid I'd have prob seen the leak when putting smoke into the vacuum lines.
I did test the vacuum reservoir on the old VC just pulling vacuum with the new tester. I made the mistake of having the VC not horizontal and filled my vacuum tester with oil!
A quick test of the vacuum reservoir would be to pull the hose from one of the outlets and draw vacuum and make sure it holds. Mine failed that test.