My car runs wonderfully, perfect boost, purrs like a kitten except recently when I launch hard and the weight shifts to the rear it's like the engine turns off for 1/2 a second and then comes back to life. I thought maybe fuel slosh, but it does it with a full tank. After launch or if I ease it out on launch the car shows no other signs of problems. Anybody seen this before?

 

from what i understand, you can still experience 'slosh' w/ a full tank, as the gas isn't literally filled to the exact top height of your tank... an inline pump and a surge tank might be in order...

 

Here's the thing, this only started recently. A few months ago it never did this. About a week ago my vac hose from the purge control solenoid popped off, and I found out that the check valve was flowing both ways. I thought this might be it, but put in the new valve today and it didn't help.

 

Are you sure you put the check valve flowing in the right direction?

 

Yup. Pointing towards the extension manifold.