Hard starting

After 40,000 miles my 06 S/W has has some difficulty when starting cold in the am.After the first start up it seems to be OK for the rest of the day.I have no problem with high speed performance. I have recently done all the maintenance items and now I am leaning toward the fuel pressure regulator. I have not looked at It but was wondering if there could be a indication of a problem if a trace of fuel is found in a vacuum line at the regulator. I guess my next step would a pressure test. Any thoughts would be appreciated.   Howard