I'm getting a noise like some one snoring coming from my gas cap on my 1997 F150 4x4 while the truck is running. I have replaced the gas cap. I know that a new fuel pump was installed back in August. If I open the cap pressure is released. Is there a pressure valve some where?

 

Maybe a pinch or restriction in the evap line when they did the pump. I would try to follow the lines from the tank and see if they are in good shape

 

Maybe a pinch or restriction in the evap line when they did the pump. I would try to follow the lines from the tank and see if they are in good shape

 

Maybe a pinch or restriction in the evap line when they did the pump. I would try to follow the lines from the tank and see if they are in good shape

 

A friend of mine is haveing the same problem with a Crown Vic.

It is also affecting how the car runs. She had the shields put on for the exploding problem and it started to happen. Mabye it has something to do with those evap lines.

Mike

 

I took off the charcoal canisters and one was blocked. I cleared them both out and replaced them and the noise is gone.

 

Did you get a check Engine light while you were hearing these
noises from the tank/fuel cap?

 

No there was no CEL that came on for this. Just a snoring sound from around the gas cap.

 

Thats weird that there was no CEL on since you said the canister
was blocked. Im haveing the same trouble with my truck, but my
CEL is on. I have been told it is my evap canister, so as soon as I get some warm weather im gonna take a look at mine too.

 

I was getting a p0171 p0174 awhile back. But that was the fuel pump pressure was low. I went on and put everything new on. 02's. EGR, TPS, fuel pressure regulator, another set of vacuum lines, I made a new PCV line out of 3/8 steel line. It run strong now.