only 150 miles out of a full tank! 11 mpg!

hi, this is mostly town driving but i used to get over 180 miles out of a full tank, she drives pretty well, idles fine and have my own gastester and co2 is correct, according to the machine atleast. checked plugs and they are black and sooty, which i guess means she's running rich, does anybody have any ideas of what else i could check.

most of the usual culprits have been changed such as

- leads
- dizzy cap
- rotor arm
- coil
- ignition amp
- airflow meter(used)
- ecu(used)
- fuel pump
- temp sensor
- thermotime switch

any ideas would be greatly appreciated
thanks

1988 3.5 efi manual rangie

what about the right foot??????????????

I would get a good tune up if i where you! 150 mile per tank is very poor for a 3.5 v8 efi! I owned a 89 3.5 efi auto which i could easily get 17mpg out of her easy round town! And if light footed get 20mpg on a run!
If taking it semi easy down motorway traveling about 60-65 mph i could get about 380 mile+ on a full tank!
I have asked around most people who have owned similiar rangies all said definately should be getting 15mpg+ round town! so i would definately look at your engine! Fuel system/injectors/fuelfilter!!!!/airfilter etc.
Just too add i am usually towing a caravan as well on longer journeys! so i probably could get more!
see what u come up with!
Silly question have u put some injector cleaner thru system!
have u checked cold start injector in plenom chamber.
The simple things like airfilter could cause problems i changed mine for a k+n type element much better cleaner burn as more air getting in!
And have u changed both fuel filters as this could cause problems if cloged most people forget that it has 2! Also check your 1 way valves fitted on vacuum system i found 1 of mine was faulty causing uneven running! not you symtoms i know but u never know!
Hope u find your problem if not you may be better sending it into a tuning specialist to get things checked out to see what they think! ok