So got this little 2012 Pop Automatic with 214,000 miles for next to nothing and in need of some TLC. Over the two months I’ve been there tinkering on it on the weekends. I live about a mile from work and minutes from the grocery store so till last week I had only drove when needed until I’d finished the suspension repairs. This past week I made a point to drive it as often as I could because I wanted to see what else had to get worked on. Sunday I filled R up and was kinda shocked to
see I had only gotten 22 miles/gallon out of that tank full. I definitely wouldn’t say I was driving it extremely aggressive but wasn’t putting around the whole time either. So I’m wondering what else I need to look at. I understand it’s got a lot of miles on it but 10 miles/gal under average seems like alot to me.

What have I already done:
front struts
front lower control arms
rear shocks
rear & front brake pads
tires & alignment
spark plugs (they were burnt 25 thousandths over gap spec)
timing belt, water pump & coolent flush
oil change with filter (twice, first when I changed plugs {the oil was absolutely foul} then again when I did the timing belt, that time I changed the the Multiair oil filter as well.
PCV valve and PCV housing flush
aftermarket intake from previous owner, changed air filter (k&n)
drivers & passenger side motor mounts
replaced engine to body ground

still to go:
exhaust flex pipe, decent size hole, makes it sound cool
rear motor mount, was sent the wrong one wait on the correct one
bottle of injector cleaner

What else should I look at that can effect mileage? Does it have a mass air sensor the can be cleaned?
One other thing I noticed is when I start it cold it’ll studder for the first few seconds. Not sure what that’s from yet.