Ford 1998 windstar 3.0l, when open gas tank cap, air pressure release sound occurred immediately.Although replaced a new cap, the situation is still exist.

Maybe taking the gas cap off releases pressure on vacuum in the gas tank. I'd have to check your evap system. I'm just thinking out loud. Might be other issues?

Replace the gas caps with new. It sounds like the vent in the original gas cap is stuck and not working.

sounds like the gas cap isnt releasing pressure have you replaced it

Well code 1450 for a Ford product is a problem with the gas tank venting system.
I would think the pump in the tank is blowing the fuse, and it could be from excessive pressure in the tank.

you need a new cap they have a presure release built in

Mine was the fuel pump there's a valve on there I think it's a pressure sensor built on to the fuel pump 03 Ford ranger 4.0 I just put the new fuel pump in 3 months ago this is my third fuel pump there's three to four things to check the canister pressure sensor and the other sensor underneath the hood the SUVs in the Ford expedition has the same setup just about

it is in the tank. You must remove the whole gas tank to replace it.

the fue TANK pressure senson is on top of the gas tank, there is no pressure sensor on the fuel rail, you have to use a fuel pressure tester.

There is a system for removing vapors from your fuel tank to protect the environment.
As u use up gas, the tank has more space to accomodate vapor from the gas. When u fill up, this could expand out thru the gas filler pipe and in the air, and be potentially dangerous.
So there is a pipe that leads from your tank to a charcoal canister. A pressure sensor reads the excess pressure in your tank, then opens an electrically controlled valve to allow the vapor to pass thru the charcoal canister, cleaning out the dirty pollutants, and releases the gas into the atmosphere.
A faulty gas cap means that the pressure sensor never reads any pressure and tells the computer that the valve has not opened. The computer then throws up a code indicating an evap leak.

So 1st, as your man said, change the gas cap. Have the engine light switched off at your local garage, or autozone, then drive and see if the light comes back on.
If it does, the evap canister for your vehicle is slightly behind the fuel tank. The spare wheel need to be removed, then the evap canister can be checked out. There are 2 or 3 bolts holding it on. It should be lowered and all the pipes inspected for leaks. Many garages will check for this leak for you with a smoke machine.

Last one I fixed had the inlet pipe eaten by a mouse/rat.. there may be some odour that attracts them. Cracked pipes are common.

Hope that helps some....

Never owned one but maybe your car is Vapor locked...It's when your gas tank pressure becomes greater than your fuel pump..It's caused from years of over filling your gas tank...Your car is designed to burn vapors. But gas goes down the line instead and clogs up your canister meant to filter fumes...Then it builds pressure up in the gas tank. When the pressure in your tank becomes greater than your car...It shuts off and want start back until the pressure has gone down...If this is the problem just loosen your gas cap...it releases the pressure immediately...You usually will hear a suction sound when you open your gas cap....Hope this helps...It could be the problem...maybe not...But something you might not think about or know