So I'm getting about 14 MPG. I'd think i could get at least 17-18. This is all city, btw. It's getting quite expensive to drive.
Anywho, here's a list of things that have been replaced for one reason or another since getting the car, without a mpg improvement:
Air Filter, Spark Plugs/Wires, Fuel Filter, O2 Sensors, Rear Caliper (passenger side. Rotor on that side also), All brake pads, oil/filter (several times of course), Transmission fluid/filter, tires.
I've tried cleaning the MAF, IAT Sensor, and Throttle body.
Car is entirely stock, save for chrome stickers in the lettering on the car's butt =P

Things that come to mind that could still be the problem are a leak (as I get nearly twice the mileage on the freeway, and it seems to use some fuel even when I don't drive it for a few days), or the EGR (although I only mention it in passing, cause I've only read that its removal or defection can really hamper mileage. haven't actually looked at it myself). So far I'm leaning towards the leak, but I can't find evidence of it besides the car seeming to use fuel when not being operated. Anybody have any suggestions on what else I should check? (and how I should check it, if i'm missing something in something I already think i've checked)

 

well lets start with how do you drive your car, are you full throttle all the time or driving like a grandpa

 

grandpa driving FTW

 

I accelerate slow enough to frustrate people behind me, so more grandpa-like than full throttle, but I don't stop accelerating until I'm [Speed Limit]+5. Also, in the past, I did an experiment where one tank I used a lead foot and the next tank I drove grandpa style, and didn't notice a lick of difference, but that was over a year or 2 ago, so idk how relevant it may be still.
Generally I only give it what it needs to get going, unless I'm in a real hurry and need to cut someone off without getting rear-ended.

Also forgot to note that I use fuel injector cleaner often... about twice as often as I change oil, so they shouldn't be too dirty. Good stuff, too (or, at least, what I'm told is the good stuff.... Lucas brand). However, I wouldn't put it past the injectors to do this to me... the previous owners didn't take too good care of the engine... just the outside. I changed tranny fluid about 5k miles after I got it, and the dust plug was still in the bottom of the pan (had [high-70s]k miles on it at that time)

 

you drive a mustang....stop bitching about gas mileage

 

easy for you to say... you don't have to eat the bill for my gas. I'm not complaining about bad gas mileage in general, or i would have bought an Accord or something instead. I'm complaining about getting bad gas mileage even for a Mustang.

Stop complaining about my complaining =P

 

i get a bad gas mileage, and i drive my stang atlest 40 miles everyday. so a week of driving casts me about $60 a week

 

i get 21/25 in mine. i cant think of anything right off of the top of my head that would help you. put a big piece of cardboard under your car at night to see if any fuel drips down. you could get a set of udps. they usually help a little bit. that obviously doesnt fix your problem because stock you should be getting better mileage but it would help get better mpg.

 

my neighbors 2000 mustang started leaking fuel at the fill to the tank due to a bad o-ring. you should smell fuel if its leaking though

 

thats a very common problem on these cars so its very possible thats at least part of it.