85 911 - no start. Yes another new thread!

[MANichols1]

After 3 years of ownership the ol girl let me down for the first time ever!! After a unusually long crank this morning, she finally started. I pulled out of the garage and she died and would not restart.

I've swapped DME relays with a known good, no change.
I checked fuel pump fuse, good.
Car will run on starting fluid.
Fuel pump and filter were replaced in January.

After reading as much as I could here on Pelican, I'm still a little unclear about next steps.

I want to check fuel pressure and will need to purchase a gauge. Can anyone confirm that your typical fuel pressure gauge kit from AutoZone, Harbor Freight, etc will work? I read about some disagreement on this.

Thanks from a 911 problem solving newbie.