HELP fuel/gas mileage problem HELP

[xfasteddiex]

i am getting about 80 miles to a 1/2 tank of gas on a stock 91 gt vert auto transmission i was told it was mostlikely fuel pressure regulator any thing els i could try i also noticed a vaccume line rotted it comes from under intake down to a box under air cleaner  PLEASE HELP 

[Soaring]

Sounds like you need to start with a general tune-up to get all the worn out parts such as spark plugs replaced and the timing set, etc.  Take her to a Ford house and get a tune-up, then report back to see how you fared.   Using K&N air filters and keeping the lead foot out of the accelerator also helps.    I got 26 MPG today going about 200 miles on the freeway in 5th gear going about an average of 70 with my Mach1 32 valve 2003 4.6.  So, you are really sucking with mpg with that 91.  Get her tuned up.

[DonB]

Big difference between my 83 and yours, however check your vacuum lines. I had a mechanic leave just ONE off, and my mpg went down to about 5!! I didn't find it until after I replaced the egr valve and a bunch of other little things. Turns out it was a 75 cent hose off the air cleaner. A tune up helps too!!

[rmodel65]

ok something is definitely wrong. i get 350 mile per tank full on the road and about 270 around town. you need to do plugs,wire rotor, cap. you need to clean the maf sensor(its in between the air filter and the throttle body) you need to advance the timing to about 12-14 btdc look at the fuel pressure also make sure all the vacuum connection are good also. also i recommend running a can of seafoam thru the engine pull the brake booster vacuum hose loose and start the car, insert the hose into the can slightly let the vacuum suck about 1/3 of the fluid out and turn the key off. let it sit for about 15 min then restart the car. if its real dirty in the motor it will put on a nice smoke show. then add the remainder of the seafoam to the gas tank

[xfasteddiex]

did the sea foam first tank full all vaccume leaks fixed maf sensor was bad so was 02 sensor on bank 1 (passenger side )i have 2 friends that are mechanics for local ford dealer they were finaly able to hook up car to computer yesterday i got every thing fixed they also told me i should pull egr & block it off & pull smog pump .ill post more on how mileage turns out next week hopefully my next tank will last that long LOL

[Soaring]

With all that repair, you should see a huge difference in mileage.  Let us know......

[rmodel65]

if you wanna delete the smog pump do not buy the bracket just buy a 770K6 belt it uses the stock routing and is a lot cheaper than the delete pulley. then just block off all the loose hoses etc

[KJ]

Hello.

Have you tried installing a Cold Air Intake system on your mustang? I heard that they improve mpg...

[66GTKFB]

After reading thru all this about milage, the solutions may be all proper and workable, but to really know what your perormance and milage is, you need to develope some driving and owning diciplines - namely recording your distance traveled and number of gallons of gas you put in. Going hand in hand with this is filling the tank full every time, not just to put in $20 at fill-up time. You divide the miles traveled between fill-ups by the number of gallons and - bingo - MPG, not this half tank stuff. I use a spread sheet for all my cars and the data goes back to about 1987. Any type of deviation and I want to know why. Prior to that, I used a circular slide rule. Anal? Nope, practical. It's a dicipline I learned from pilots, truck drivers and race car drivers, all family members.
Jim

[Soaring]

After reading Jim's message above, I thought I had misread your post, but after reading it again, it seems you are filling up your tank, then driving it until it is halfway empty, then filling it up again and checking your MPG that way.  That is what you are supposed to do.  Never drive your car more than halfway on the tank.  And, when you do fill up, only pull the trigger halfway, and after it clicks off, stop filling.  Do not cram more gas in the tank.   That way, you will have a better idea of just how many gallons you burn per miles.  That car, if driven responsibly, should be getting around 18-20 MPG.