: gas pressure in gas tank

04-01-09, 09:56 PM
I am getting this issue and I appreciate your help on the topic.

I have a 95 Fleetwood Brougham.
After driving for a couple of hours on the highway and usually if the tank is less than half empty, i start feeling a counter pressure whenever i press on the gas combined with strong hesitations. To the point that if i am slowing down near the exit, the car can and do caugh and stop.
It is like the fuel pump is not working. However, When i stop to fill up, here is what happens.
When i open the gas tank knob cover, you can hear strong pressured gas leaving the tank.
Then i fill it up and the problem of hesitation goes away and all is fine.

Help! what should be done to fix this problem?

Aslo, how can i pull the computer codes from the 95 Fleetwood Brougham?
I used to pull them on my previous 89 Fleetwood, and it was like the Devilles. This one is different.

Thanks for your help.

04-02-09, 01:11 AM
you can access the code through the hvac controls, info is in this link

these cars have some issues with the fuel pump wires, melting and making poor connections,
also you might try replacing the fuel filter , since its an easy one to do, and could cause your issues
having the pressure in the tank is not unusaul, my 94 will build up as well, mostly on 1/4 tank or less, follow the instructions and see if you pull up any codes, then let us know

04-02-09, 07:14 AM
Do you thing the tank is releasing air or inhaling air. I think the tank is building vacuum inside due to a clogged or pinched vent line.

04-02-09, 09:41 PM
Do you thing the tank is releasing air or inhaling air. I think the tank is building vacuum inside due to a clogged or pinched vent line.

Absolutely. Check the charcoal canister. Not sure where it is on a 94, is it still under the hood? They have a filter that can sometimes be changed, but see that it has not got a constant vacuum on it. The canister control is supposed to do a purge on the can once in a while, and then shut off. If it's got a clog somewhere and is drawing a vacuum on your tank constantly, that isn't a very good thing.

This can actually collapse a fuel tank under severe circumstances.

Once you find and repair the issue though, it's good to know that your fuel system is that air tight- actually....

It's not legal to use a vented fuel cap on a 1994 car, but it would not hurt to leave it loose or absent as a 'test' to see if the problem goes away once the vacuum on the tank is released.

04-03-09, 12:09 AM
It is releasing air when i open the fuel cap.

04-07-09, 03:06 PM
im having the same exact problem, and today i drive to school with my gas cap off and the car felt a bit more lively under acceleration. my dad says that some gas caps vent themselvs.... is this true? looking at it i dont think so.

my car is a 1990 brougham.... can any one point me towards where the charcoal filter is? until then ill just keep my gas cap off.

04-08-09, 12:22 PM
1990 has a 307 with a carburetor, right? That should definitely not be holding that much of a vacuum. I know for sure on the 307 that the charcoal canister has a filter, I'd look at changing it.

The gas cap is not vented. I think they stopped doing that in the 70s.