86 accord LX-i

ok, i have been looking at other accords like this one and the gas milage that they have been getting. i see all of the time these cars getting 30 or more to the gallon. my car is getting at most 27. I am selling this car and i don't want this person to end up with some outragious repairs. the mpg seems a little low for a 4cyl. engine to me. what could possibly be the problem?

The car idle's rough, my mechanic said it might be missing, or it sounds like it is missing, is there any way that i would know if this is the case? what can i do to fix this? Do i have to have any special tools?

ALSO.... when the car is warming up, it's about a 1/4 up on the temp gauge and it idle's where it should (700-800 rpm), but when it get's 1/2 way up, where it usually stays, it idle's at about 1200. I don't think this is normal

thx.
BTW, the car is an 86 Accord Lx-i with 241k miles.

recent timing belt,
fuel pump
fuel injectors
destributer (remanufactured)
TW sensor
spark plugs
wires
tune up (however, i don't think this is valid anymore, due to some of the tinkering around i've done)

ALL ideas and suggestions are appreciated!
thx

is your timing on the mark?Also what about your fuel filters?
I know those arent gonna solve all your problems but also, what did you tinker with?

Check for vacuum leaks. That will give you a very rough, vibey idle, and can affect fuel mileage and temp. A lean (too much air) engine runs warmer than normal. It is possible and not all that uncommon for a loose carb or intake manifold to get looser as the engine warms up. Get a spray bottle and spray water around the base of the carb, intake manifold gasket, and vacuum lines the full length and see if any change in engine idle speed or smoothness is noted. If so, you've found a leak. Do this with the engine at full operating temp.

Also at 241K, it is possible that it is just getting tired. Intake valve deposits and valve seat wear take their toll on power, economy and idle stability, even on a Honda.

Disregard the carb reference, I missed that it is FI. But the rest is still applicable. There is an adjustment for idle air mixture near the throttle plate that usually needs tweaking on Hondas with any kind of mileage on them. Turn the screw out slowly until the highest, smoothest idle is acheived, then turn it back in until the idle just begins to drop again, and leave it there. Then set the idle speed to spec.