Okay, I just had the fuel filter (AC Delco) replaced on my '90 IROC. Then I went to the gas station and filled the tank up with 93 Octane and then added STP Fuel Injector Cleaner. I drove the car for like 2-3 minutes to my friends house and shut it off. We came back outside like 10 minutes later and smelled gas VERY bad. We looked around to see my car POURING gas from the gas cap! We checked the cap, it was tight. The car was level. It continued for like 10 minutes!! It would NOT stop. Finally, we started up the car and the 'vaccum' or whatever pulled the flowing gas back into the tank. I shut it off and it didn't leak anymore. What in the world just happened?! Is this thing safe to drive or what?!?!

-Thank

 

Ive never heard of that before, but it sounds like your tank is not being vented and is building up severe amounts of pressure.

 

Damn, that's odd. You got me on that one.

One thing I will say is that the gas cap should contain the fuel even if you were to park the car on a 45* angle. This is NOT the whole answer but I'd recommend you go pick up a fresh Stant gas cap at the local auto parts store that is designed for your car. Many caps look the same and will physically screw into place, but they won't seal up. I had an old 91 RS that someone screwed an incorrect cap onto. It would screw down tight but every time I accelerated or turned real hard, gas would come pouring down the fender. A correct cap totally fixed the problem.

 

I don't see how a fuel filter change could cause that either... unless the filter's blocked. Did you install it in the right direction? How much gas was in the tank, anyway?

 

I had a local shop put the fuel filter on when they were doing some other work... so I didn't actually see if they put it on right. After it was replaced, I drove about 3 miles and parked for about 45 minutes. Then I drove about 30 minutes and pulled over at a gas station. I filled it up to $21.47 then it kicked off. I pumped it up to an even $22.00 then added the STP treatment. I drove about 1 mile to a friend's house. We noticed the gas pouring out about 10 minutes later. Is it possible that the STP caused some type of 'reaction'? The car was level, so it should NOT have had anything to do with the gas cap. I didn't see any problems today while driving it

-Thanks

 

sounds like the tank isnt venting at all. If you dont have real strict emmisions laws you can just pull the ball valve out of the plastic relief valve near the gas tank and reassemble it. The tank will now vent regardless of whats blocked on the way to the charcoal canister.

Oh, btw, dont overfill it next time.

 

Dude he didn't overfill it. Most vehicals will click off well before the overfilling point. I have fit an extra 2 or3 bucks in when I was filling my car in. That is overfilling (my gas came right to visible range)