All of a sudden... Sluggish

Hello Everyone,
I had a strange occurrence happen yesterday Which is puzzling me & I am hopeful that the group can put me in the right direction.

My 72 GT has always run very smoothly without any hesitation. Yesterday evening, she started up fine and I drove across town to pick up my daughter about 2 miles from my house. I waited about a 1/2 hour for her to be finished & left the car idling while I talked to some other parents. When I got back in the car to go home, the car noticibly lost power & sputtered all the way home. This morning when I started her again, she still sputtered.

Any thoughts to help me set up my weekend project would be greatly appreciated.

Bad Gas?
Spark Plugs?
Timing?
Fuel Line?
Drop the Gas tank?


Thanks for any input.
Marc