i have a 92 camaro rs with a 3.1(for now). i have noticed that when i take the fuel cap off i have alot of pressure being let off, i think that it is pressure escaping, but after reading some threads i never thought about it being a vaccum. Regaurdless there is alot of pressure being built up. im not the most knowledge filled person when it comes to cars, im just learning as i go. i dont think the fuel cap is vented, i pretty sure there is an atmospheric tube that is supposed to relieve pressure. the car sat in kentucky for three years or so with the engine blown. i have changed out the fuel filter and ran fuel injector cleaner through it.. i have no fuel leaks, but today after driving it i noticed my fuel cap was loose, which i know was tight cuz i filled it up this morning, and fuel had run down the side of the car. ive been working out bugs on the car for a couple months now, mostly electronic issues. the other issue is that yesterday i changed the oil in the car after i replaced the radiator and cooling fan, and today i drove it about 10 miles down the road and when i got into town and let off the gas petal my oil pressure dropped to 0, but went back up to normal when acclerating. When i was done with softball practice i started it back up, oil pressure read normal, drove through town, oil pressure normal, got on the highway to go home, got back into my town and the the pressure did the same thing, no oil pressure when not accelerating, normal when accleerating. i read that fram oil filters are garbage( which i have always used) and that one individual had the same problem and switched the filter out and it fixed the problem. the main bearing in the engine are new( only 800 miles) and the car shows no signs of the bearings going out. i would appreciate any advice i can get.