Gas Cap?

[Calabrio]

Does the gas cap eventually wear out and will this affect either the fuel effeciency or the accuracy in which the Mark VIII tracks fuel consumption?

In my case, I never have heard any release of pressure when removing the gas cap from my Mark VIII, as I do in my other car, despite having installed a new 255lph fuel pump.

Also, the computer is recording inaccurate gas mileage and fuel consumption. It's been reading about a full gallon difference between what it displays as being consumed versus what it takes to top off the tank. After 60 miles last night, this difference meant a posted mpg of about 27, though it actually was about 21.5 mpg.

 

[Frat-man-du]

My cap seal went out on my 00 stang. Drove like crap till I replaced it. Actually I believe it caused the pump to die an early death ( 65K) because I let it go for a week.

Stangs don't have a mileage calculator so don't know if it would make any difference.

I went out and open my filler on my 98 LSC - no noise, but it has been off overnight so not a true test. I will drive it and then pop the top and will post if it hisses.

 

[Frat-man-du]

Ran for 10 minutes - slight - very minor hiss when removing the cap.

 

[Redwingvksm]

Does the gas cap eventually wear out and will this affect either the fuel effeciency or the accuracy in which the Mark VIII tracks fuel consumption?

In my case, I never have heard any release of pressure when removing the gas cap from my Mark VIII, as I do in my other car, despite having installed a new 255lph fuel pump.

Also, the computer is recording inaccurate gas mileage and fuel consumption. It's been reading about a full gallon difference between what it displays as being consumed versus what it takes to top off the tank. After 60 miles last night, this difference meant a posted mpg of about 27, though it actually was about 21.5 mpg.

You may hear a SLIGHT hiss (as in earlier post) but nothing extreme. Just a slight vacuum.

That DOES NOT affect gas mileage.

When you top off a tank - there will be air pockets on the very top. Thoes MPGs are only estimates - don't take them seriously (from the car) just use your own. That is the best it can come up with!

 

[Black87LSC]

I don't think I've ever heard a hiss come out of my filler... As far as I know it's not "supposed" to. I didn't know they could go bad, can they really?