Anyone who has similar problem or experience, please reply.
My Fast idle thermo valve is faulty and I'm running at 15in Hg of vacuum at idling. Can a faulty Thermo valve reduce the amount of vacuum I'm getting? Or should I go ahead and replace all the hoses and gaskets on the intake manifold? Thanks.
PS. I've checked all the hoses and the TB gasket.

 

What made you suspect that your fast idle is at fault. Yes if your Fast idle is open, whicich it does during cold start-ups it will let more air through the throttle. This will give you a high idle and your vacuum will drop. It' sounds like you have a little vacuum leak.

 

Thanks for the reply, well the thermo valve was sucking air even when the engine was at operating temperature. However, I DO NOT have a high idle but the idling fluctuates (hunting idling 500 - 1000 rpm) when its warm and remains pretty stable (750 rpm with a 15 inHg vacuum reading)when the engine is hot. I do suspect a vacuum leak somewhere, but I don't understand why would a gasket break without apparent reason (the hoses seem to be in good shape).
Should I replace TB and intake manifold gasket anyway while I'm waiting for a new Thermo valve from Acura?

A couple of things I've replaced or checked so far:
-Timing belt (replaced)
-Timing checked (16 degrees)
-Air filter
-Fuel filter
-Idling Control Valve
-Bled coolant