dentman

Started hearing honking noise after cold start stutter -- dealer said new MAF, Throttle body boot and new Diverter valves would cure the problem, so I order bi pipe from a place in Ohio and they send along 2 free OEM Bosch D valves for a 225 TT.... So I put 'em in and now it feels like there is no boost. Could the TT D valves change the boost delivery time? I also opened one up from a stapled OEM box and a little piece of plastic fell out - looked like debris from mfg process, about 3- 4 mm square
rough on one of four sides like a broken recording tab from a VCR tape, only much smaller

Singletrack

boost should actually come on quicker (snaps shut more quickly). Although I doubt you would ever notice this. I have opened several diverter valve boxes and nothing has ever fallen out - that is cause for concern ; (

You can test the valves with a simple vacuum pump, or you can connect a line and suck on them to see if you can hold them open.

The valves are naturally closed (the spring holds them shut). In the car, they are open and recirculating at idle. When you get on the throttle they close, and force air into the throttle body. If one is broken, it might be stuck shut and forcing boost to the TB all the time. This could in tern cause an overboost and throw the car into limp mode. In limp mode you will not boost past 5PSI (stock is 9 PSI). Just a guess.

-st