When I take a hard right turn and my tank is 3/4 or more full, I can look back and find foot-wide dark spot on my primer comin from the fuel door. Ahh, i'ma leakin out the filler cap. Cap is OEM and the seal looks fine, tightens down and what not, but this is annoying and probably killin my mileage.

Surly I'm not the first for this. New gas cap??

This is interesting that you have this problem. The reason being is that the OEM/stock/factory gas cap on my '92 is difficult to tighten down. It binds up and the cap clicks before being fully seated. This issue is more severe in the hot summer months.

And, if I don't make sure that it is correctly tightened, fuel spills out.

Also, check to see if it is the correct cap. It may also have been modified (POS - previous owner syndrome).

Do a turn test in a parking lot and stop. Check to see if the cap is leaking through the top, or out the sides.

Yea, it's a mileage killer. . .

RBob.

You know, now that you mention that(the binding), that's probably why tightin' my cap feels the way it does. It's been rainin all week here on the universe's butt cheek, but I'll do the parking lot thing when it dries out. IIRC, inside the fuel door, it usually covers the bottom third of the trim. 'bout a 120* spread.

I get no "psssss" noise when I release it, even when the tanks almost empty. Do you guys get a noise. Maybe it's not sealing very well at all.

Cap appears stock. As stock as a gas cap looks. Is there a noticeable difference I should look for.

This car had practially no POS...then my roomate wrecked it.

Have you found a solution for the binding cap? Are today's replacment caps less likely to bind. Or should I focus on thickening the seal so it'll meet the neck.

You may also want to check the inside of the gas cap. Mine had a hole punched in it (POS), so I was losing loads of fuel on right hand turns!
The members of ThirdGen.org soon put me right

Mark.

Well, no hole in mine. I'm gettin' a new cap by next weekend and I'll pay attention to how it tightens down. You know, for bindin' and what not.

Thanxs for your time guys, I'll let you know if that doesn't work.