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Discussion Starter · #1 ·
I wanted to throw this out there for people struggling to track down boost leak issues, this might be something worth checking out for you. My issue has been that at max boost the caR would flutter between 14-16psi, sometimes way overshooting, and power would be cut as if you were redlining. It's a really strange feeling and you have no confidence accelerating at WOT.

I was in the process of installing an Elevate AMS and in doing so you need to shorten a hose to the brake vacuum switch (original part 30645457) to relocate it. Well, while I was disconnecting the hoses and electrical connector I could hear a hissing noise like there was an air leak. Closer inspection showed the top to the switch was broken and no longer secured shut, and in playing with it I snapped the top off and the spring inside shot out along with bits of plastic. They don't make part 30645457anymore and the replacement is part 31400693.

Once I replaced this part I have had no boost issues; the caR will build boost normally and sustain 12-14psi without a problem. This brake switch uses vacuum from the intake manifold to maintain pressure on the vacuum pump for the brake booster, if I understand correctly. So if you are having similar issues take a look at your brake vacuum switch and see if it needs to be replaced.

I'll be able to upload pictures later if it will help.
 

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Discussion Starter · #3 ·
The stutter you describe is usually coils and or plugs going bad.
I agree, I changed the plugs and it definitely made a difference but the problem didn't completely go away. I have very occasional misfire still and that is not affecting anything as far as I can tell at the moment, so I might start swapping coils around. But as of right now, I have no boost issues and changing this brake switch was the only thing I did (except the Elevate AMS, but I can't see how that would make a difference).
 

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Had you ever had the "ice mode" braking symptoms before?
 
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