I have sprayed the better part of a can of TB cleaner all over the intake, vacumn lines and manifold area trying to find this leak. Logic would seem to indicate that the problem is related to something that happened when I removed the intake to clean the MAF sensor and TB. It would be unusual, I think, for an engine with less than 75K miles on it in Socal to develop a manifold gasket leak.
I will keep looking.
Thanks for all your suggestions.
LLL