Running rough

A more specific question for my 1995 Mustang with 122,000 miles. It’s in pretty good condition, but lately the performance has been a little sluggish, especially when I drive through hilly country. When I give it gas, it feels sluggish and it seems like it wants to go faster and smoother, but just can quite get there. The transmission seems find and the when I took it to my mechanic, he felt it was running find.

Last tune up and what was done or NOT done? Fuel filter changed?