hissing from back of car

[henstepper]

I took my car out of the garage, went to close the garage door and heard a hissing sound coming from the rear of the car. First time I have ever heard this sound. It lasted for about a minute then stopped. It sounded like air being let out of the tyre, but I checked the tyres no obvious signs of leakage. I went to the servo and tyre pressures were ok. I let the car sit then started the engine to see if it came back and didn't. What could have been the cause?

 

[Trevor loves holden.]

Snake fell off as you drove and no longer there.

 

[henstepper]

I would like to think it was that easy but it's coming from the fuel tank I have discovered. So that tells me it's excess air in the fuel tank and it letting it out. Now what i don't know if that is normal because I have never heard it before. Or if it's a loose fuel cap or blocked fuel pump. I will try by a new cap seeing thats the cheaper thing to try first

 

[greenacc]

Just try unscrewing the cap before you start it. See if air gushes out. I think more likely a fuel pump / filter issue