err, i recently trying to do some tuneup for my 1995 accord lx, its a 2.2 non vtec engine, with auto tranny, for some reason my fuel economy still sucks, i get around 26 to 28 mpg range, and its mostly highway, and i also drive pretty careful,

list of the things i have done so far,

ngk spark plug wires, changed my sparkplugs from ngk iridium to one step colder laser platinum pzfr6f-11, and gapped them to .036 thou, valve adjustment (engine got a little quieter) , oil change to full synthetic both tranny and engine, new oxygen sensor (denso)

few things i noticed, when i was changing oxygen sensor, half the bolts that held the exhaust manifold to the engine were loose to the point where you could undo them by hand, also my car runs out of gas at around 13.5? gallons, i parked it, it was almost at the E mark then in the morning i tried to start and it would start sputter then die, i ended up adding a gallon of gas and then fueling up another 12.5 at the gas station, and i never have any problems unless i get it get that low..

the first thing i have done was change sparkplugs and i was pretty sure it helped because i did full highway trip, and i calculated 31.25 mpgs, with 2 passengers and ac on, after that i changed my wires to ngk wires, and thats when i noticed that my economy went down, the old wires i had were napa, fuel plus or something, but they were very cheap and anytime i would pull them out they would come out of the rubber tubes and i would have to crimp them back together, and they didnt seal properly

and yes i do my mpg calculation by fueling it up to till it auto click off then setting trip meter at 0 and then dividing miles of trip by gallons i fill up to the top next time, i even use the same gas station.

is there anything else i could do to tuneup the car that could help , with efficiency?