You're not too far off...
Here's a list of things that may help...
BTW, I have the 5 speed trans.
I guess I could check out a few things to improve my fuel economy, but it is still much, much better than my Dodge Ram, and a little better than my Turbo MR2. So, I am saving money by having my P5 back again.
As for the list:
I just changed the Air Filter, and until recently, I used a K&N since 03.
I think my VICS solenoid is bad. Or the VTCS, I can't remember which one was bad and causing a CEL. I just swapped them, and the CEL went away and didn't come back.
I can check the coolant, I might do a drain and fill anyways.
I have changed the coils, plugs, and wires many times over the years.
I use higher octane premium fuel.
Not sure what the CMP sensor is.
I recently changed the FPR, fuel pump and filter assembly.
I just changed the PCV valve.
One of my brakes is dragging.
Not sure about the timing.
I recently replaced my MAF with a cheap china-made one, I might put the old one back on.
I will check the compression soon, but I think it is okay.
I think my exhaust might be partially clogged in the cat, but not sure if I want to bother with this issue.
Not that it makes a huge difference, but I use slightly larger Diameter tires in the summer, and a moderately larger diameter in the winter time. This would slightly affect the perceived average MPG do to the less revs per mile, and maybe the actual MPG due to the added weight.