What oil pan are you running on it, and how much oil is in the engine? As others said, with the screens installed, maybe your oil isn't draing back to the pan and what little is in the pan runs away from the pickup..... Another thing to check, is the carb way too fat and methanol getting into the oil and thinning it out to the point it won't register pressure???? Had a stuck injector do that to me once. I'm sure a carbed motor could do the same thing.....