CGT upshift light (switch), and smog

[auditude at cox.net]

Hi folks,

My Coupe GT failed smog today, so I poked around under the hood tonight.  It failed for oxides of nitrogen (NOX), which I attribute to the significant ignition advance I had and didn't bother to adjust back prior to taking the dyno smog test.  

The limit is 2.50 grams/mile, and my result was 3.02.  The HC was 0.49/1.60 and CO was 6.66/15.00.  There's a Blau 272 cam in it, which it passed with fine last time.  I discovered my plugs were really bad single electrode ones, so I put in some new 3 electrode W7DTC's that I had.  I also went through the trouble of replacing the air filter, which wasn't that dirty it turns out.  

Anyway I'm pretty sure it will pass the retest, altho' it does have a bit of a miss or lope to it.  My question now however is about the stock upshift light.  Mine doesn't work, but my vacuum advance and hoses are good.  I sucked on that little doohickey that is inline with the hose to the vacuum advance unit and it leaks vacuum.  I'm thinking it shouldn't.  I'm also wondering what it does.  My guess is that it is the vacuum switch responsible for the upshift light, and its leaking vacuum is the reason my light's not working.  Maybe it leaks enough so that the vacuum advance doesn't work either.

Does anyone know if that's its function for sure, and if so, can I just bypass it so that at least my vacuum advance works?  I suppose I'd like to replace it with a good one at some point as well.  That's probably a dealer-only item, right?

Thanks,

Ken