I took the car for a longer drive than normal today (~150miles) and on the way home, I noticed a raw gas smell while driving. It didn't seem to matter what speed or gear as to the potency of the gas smell.

I also noticed a noticeable drop in power and mileage, so I'm convinced that its leaking.

I've checked the rails on the motor as well as I can since the motor is HOT, and I don't see anything dripping.

Are there any common failure points to check? Any idea where the smell is coming into the cabin?

 

Check your fuel pressure? My stock FPR went bad and it was burning my eyes in idle. It wasn't leaking externally, but 54lbs isn't stock. So i bought a Holley and everything is good.

 

How do I check the fuel pressure?

 

With a fuel pressure gauge hooked up to the schrader valve on the fuel rail with a vacuum line disconnected from the Fuel pressure regulator. Turn on the car and see where its at.

 

I haven't had an opportunity to check the F/P yet, but I did have another question as the gas smell seems to be occurring after the car has been running a while and is completely up to temp...

Would the gas cap have anything to do with the tank's ability to vent or anything? I ask because EVERY time I open the cap to put gas in, it lets a large "PSSSSSHHHH" out, moreso than any other car I've had... just seems a little wierd; its always like that, no matter the outside temp or how low/full the tank is prior to opening.

I've got an aftermarket locking gas cap and maybe its the wrong one?!?!

 

I would suggest getting a GM cap from a Chevy dealer. I also get that same noise when I take my gas cap off. I do not have any issues with my car whatsoever that I am aware of. I believe that is normal... this coming from the fact I have owned 6f-bodies all with V8's.

 

I get that whoosh sound and it's normal on all the fbodies Ive owned.

Look underneath the plenum and runners for wetness. I had a couple fuel rail o-rings break and fuel was spraying out into that valley under the intake.