Welcome to the forums Dan!
Do you have a check engine light on ? Or any stored codes?
Try unplugging the MAF sensor & see if starts Link: Oldsmobile 3.5L V6 Engine Sensor Locations Picture
Generally it is best to do a full tune up from spark plugs to fuel & air filter etc..
A fuel pressure gauge attached to the schrader valve on the fuel rail will give you the psi.