If you usually get gas at the same station, try a different brand/station for a couple of fill ups. See if there's a difference, you might not be getting what you think you are. Not ruling out any engine management issues you might have, but I would rule out the gas first.

 

if you have old 02 sensors change em for new. get oem some after-market 02 sensors dont like the lt1 like the bosch, have a look at the 02's in any case to make sure there not fouled. test your air and coolant temp sensors. if they are showing a really cold temp the motor will be way rich. http://www.shbox.com/1/4th_gen_tech2.html#ect
check your fuel pressure, if its high you will be running rich.
have you had your injectors cleaned and flow tested, you may have a stuck injector, could have knocked some stuff lose when you changed the filter and it got stuck in one or more of the injectors.

 

well, i have tried filling up at several different locations the past few times and all are horrible mileage. i have a 88 taurus as a DD, and i always fill it at my local bp station, and that cars mileage is always on the money 150miles local driving. i dont think its the station.

I think craby your onto something, i did put in a lucas fuel injector cleaner after i changed the filter, so maybe i loosed up some junk in the tank?maybe?

as far as i know the o2 sensors could be factory, but i thought that once they are finished they check engine would come on?

whats the right way to clean the injectors?

 

use seafoam, we use it on all kinds of things and it works great to clean them

are you sure theres not a hole in ur tank lol

 

heh, heh, or buckshot in your right shoe?

 

check or google for injector shops in your area. i sent mine to the doctor injector, its a couple hours away from me so i sent them in. had em back in three days. cost was like 25 bucks. had one that was no good and two that were plugged a tad but cleaned up nice. all were flowing under spec's except one.

 

yeah sensor walked out of my headers, but my pals exhaust was loose. not enough for code but enough to run poo.

has the milage just gone bad all of a sudden?

 

someones stealing ur gas

and im not being a smart ***, are you sure thats not the case? you live in nyc

 

well i noticed it go bad after i changed the filter that was about 5 tanks ago, but when i changed the filter i also put injector cleaner in.

side note--i just saw the news and they were talking about the bad weather that we had in a long time and they showed a black 4th gen similar to mine to coming down a ramp and the back went right into the concrete barrier and bounced off, almost brought a tear to my eye

 

i looked for a injector shop online no luck, wouldnt the engine run differently if the injectors werent spraying correctly?