When my car sits for more than 4 hours I have to try a couple of times to start it and then hold the rpms around 3000 for a minute or so to keep it idling steady. After that it works just fine and if I shut it off for a short period of time it starts up fine. It seems like if it sits too long, I have to pump the gas to get fuel to the engine. Has anyone experienced the same problem and has any advice? Thanks.