[200q20v] by-pass valve

[Brian.Link at Level3.com]

My TBV question  in more detail:

I got with my car what I think was a rebuildable TAP bypass valve (anodized
blue threaded.  My car started to develop a stalling problem, I replaced the
Blue TBV with a Bosch (stock?) TBV.  This is all black with metal reinforced
connection points (pretty robust).  The car runs better than ever...no more
stalling.  I fixed the blue one by cleaning it very well...(taking it apart
and running it through the dishwasher).  Now it does not leak, car does not
stall.  The spring tension is a lot firmer than the bosch unit,  What is the
point of having a stiffer valve?  
I am pushing around 20 psi.  

Brian Link
Boulder, CO.