My gas tank sounds like a trumpet.

[lnlogauge]

2001 4runner. v6, 250k. I've had a code for evap emissions for 9 months now. Replaced the Canister last year, which gave me all of three months without a check engine light.

The car has to be warmed up, with 10-15 minutes of driving. When the gas pedal is touched, the car makes a rather trumpet like noise in the back. I bought a diff rebuild kit thinking that was the problem, but yesterday my dad and I figured out that the diff is quiet. Its the gas tank. taking off the cap doesnt change anything. Also, the car has to be under load to make the noise. When idling its completely quiet. Speed doesnt change anything.

I tried to search for similar issues on vehicle specific forums, and nothing came up. I'm at a loss with this one.

 

[gamefreakgc]

The gas tank is under vacuum, which is why the gas cap "sucks" in air when you take it off at low fuel. My guess is that you have a seal, probably at the sending unit, that is no longer air tight and making some awful noises.

Really hard to tell beyond that though.

 

[lnlogauge]

For anyone that has this issue, I figured I would update.

I had the evap emissions system smoke tested. They checked all sensors, didnt find any leaks. I'm not sure how they determined it, but they concluded the charcoal canister I replaced 2 years ago as bad.

Went through warranty for a new canister, and all issues are gone. I'll list all the problems from a bad vapor canister.

*check engine light
*sounded like a trumpet after 15 minutes of driving
*gas pump would stop every 20 seconds when filling
*wouldn't start after getting gas

all issues are gone, car runs great now.