I'm not sure of anything on this car. I've had it since I was 20, so about 9 years. For the past 2 years, on and off, I've had this problem when I'm sitting still and the car is idling. My RPM gauge will go up to about 2, sometimes almost 3, and the engine will rev up, right along with it. Sometimes, when the RPM gauge goes back down to 0 or almost 1 like it's supposed to, it'll just flat-out die on me. This has happened at stoplights, in drive-thrus, and in my own driveway before I turn the engine off. I've taken this thing in to O-Reilly's, Auto Zone, Firestone, Big O's, and Meineke, MORE than once. They all give me different solutions but there's one thing they all have in common. All of them have said they think, or know, there's a leak in there somewhere but none of them can find it nor do I notice any pools/puddles of fluid on the ground after I turn the engine off or pull out of that particular parking spot. I've looked online and the only thing that makes any sense is that P0301 code diagnosis, but since I know next to nothing about cars, I wouldn't even know where to BEGIN to look for problems. If someone on here would be kind enough to explain it all to me in layman's terms, preferably, I'd be really happy.