kjdavis

I've been fighting a problem with my 99 GT for quite some time and I just keep getting frustrated with it. The check fuel cap light is on, and my fuel economy is tanking. Ive checked the obvious, and replaced the fuel cap with no change. Ive replaced the fuel filter, fuel pump, evap canister sending unit, all with no change. It started out that the light would be off at first startup, but after about 5 miles it would come one. Now, its just on all the time.

Anyone hae any ideas as to where I should be looking next? Thanks!

HaneyMotorsport.Com

You need to do a smoke test. Good chance you have a leak somewhere.

Casey

Sxynerd

the normal leak zone is the rubber grommet around the filler tube going into the side of the tank. try there first. You do have a leak.

gec

yup...had the same prob cost me 9 bucks and a sat mornin = problem solved

Tim99GT

I have the same problem. Just havnt fixed it yet. How would having a leak cause bad gas milage??? This wouldnt affect the pumps ability to run efficiently would it?(cause it to run lean)

I guess i have somthing to do this weekend....

Sxynerd

two things lack of pressure and the obvious leaking fuel.

Tim99GT

I get the leaking thing(but that is not going to cause a major change in gas milage unless you have a serious leak), but lack of pressure? Shouldnt there be a vacuum inside the tank though? I can see there being some what equal press due to the leak letting air inside of the tank. I always thought the pump created a vacuum. So, like asked before, would this cause pump deficiencies?

Sxynerd

I can't explain it but That's what I've always known to be true. Maybe someone else can chime in.

kjdavis

I cant explain how itd work either, but for the price, Ill give it a shot. Ive dropped that tank out so many times, should only take about an hour this evening. Hopefully it fixes it.

kjdavis

Update...

Replaced the gasket, light was off for about 5 miles and then came back on.