EVAP system... large vacuum when removing cap???

[budwich]

On my 96, when I remove my gas cap, there always appears to be a very large gush of air going in. I assume its a release of a vacuum in the system. Is this normal... I bought the truck used in the spring and its always been like this. It was a country truck and there was "dirt" in places... like the ebrakes totally "cemented" solid. I am thinking the EVAP canister air intake ports are probably plugged solid. Are they "serviceable" (ie. cleanable)? or do you need to replace the canister?

Thanks

 

[410Fortune]

canister purge valve

the lines themselves are likely fine.
You have a canister purge valve and a canister vent valve.
One is under the battery the other is behind the fuel tank with the charcoal canister.

One of them is not functioning properly.

 

[budwich]

Thanks... I will poke around to see what I can see / find. I guess one other question arises... is it possible that the gas cap isn't allowing enough air to vent in which I think is suppose to happen?

 

[410Fortune]

yes it is possible, however your symptoms to me = bad EVAP system, but I have never had a Ford gas cap fail..

an emissions place can check your cap.