Ok ... here are checks and actions taken:
- pulled vac hose of the pressure regulator .. slight gas smell ... I am assuming the diaphram may have had it ... so I ordered a new pressure regulator. I assume that all I need is a pair of internal retainer ring pliers to pull the old one out right?
- checked all the vacumm lines I could find ... the lines are all attached and look solid ... no collapses or rubbery feel to them. Engine idles steady as a rock ... so I am going to assume for now that I have no vac leaks.
- On checking the cross-over intake air pipe for leaks/cracks ... I removed the MAF and noticed some fuzzy stuff on the sensor plate ... I cleaned the plate with no-residue electronics component cleaner and dried it with my air compressor ...

I turned the code off ... and after a day ... it came back on. Checked to see it was another P0170 code ... so I decided to get a new MAF along with new pressure regulator. Got both at very decent prices from Autohauz.

I expect the new parts to arrive UPS ground on 9/25 ... so I'll have to wait to install and see what happens. Thank you very much for your advice.