My '07 feels slow to build boost. I've made no changes recently. I have no codes. If I have the time (3rd gear+) it'll reach a few psi lower than normal - it'll hit 15psi when it would typically hit 17psi in this weather (OE '07 tune.) Once it does reach boost it pulls about as it should for the boost level, no odd issues otherwise.

1st gear boost builds so slow I peak out at like 4psi in 1st before running out of revs, maybe 12 in 2nd. I swear that typically the car would build boost so fast it would spike slightly before settling at target. I also feel that this has been a gradual problem, not an overnight thing. Felt a little slow at some of the earlier autocross events, but couldn't put my finger on it. Is much more obvious now.

First plan of action was to check the diverter valve. It looked good with no tears. I have no weird noises from it (typical pshhh.)

Scoped downpipe cat. Looks good, waffle not melted, expected amount of soot on there but light passes through well.

Some play on the wastegate shaft, but I assume if it were super tight it would bind. The flapper door seems like it has a lot of play. Applying vacuum to the actuator seems to close it ok, I can wiggle the flapper a bit when closed. No idea how much vacuum it takes to close it, using my oil extractor with no gauge. It does hold position though, so I don't suspect a leaking actuator.

Here's a couple of poor vids of the actuator at work, and me wiggling the flapper door to show the play:

It seems like it closes ok, it doesn't line up perfect, but there's no obvious large gap either. Both nuts on the actuator shaft are in place and tight.

I'd appreciate any insight / stuff to check next.

 

This was how my worn wastegate looked once I was able to get better access to move it around:

 

That looks worse than mine, like your pivot shaft can rock more in the direction the actuator pulls. What were your symptoms for that?

 

 

After sleeping on it, I'm thinking I should hook a vac gauge to the wategate line. First to see how much it takes to pull that guy closed, then to see if the car is demanding enough vacuum.

Assuming that my gate is closing ok, there's only three things left, the hoses, the boost control solenoid, and the vacuum pump itself, right?

 

mine has a similar play and it works fine...maybe it's done like that so it doesnt snap from heat!?

 

Well that's weird, I bolted everything back together with no changes and boost seems to build much faster. Still missing 2psi though.

 

I guess I'll close this issue without a definite result.

I bought a vac gauge and the vac pump pegged it. I pulled the intake manifold to check the vacuum lines and boost solenoid. The lines checked out ok, the boost solenoid held vac and opened when 12v were applied.

I put everything back together with no apparent changes and the car boosts as new again.

I changed nothing and fixed it. Your guess is as good as mine.