I cleaned my fuel system about two weeks ago. I cleaned behind and in front of the flap in the throttle body, and I ran fuel system cleaner through the engine through a vacuum source on the throttle body(the one that connects to the fuel pressure regulator). Ever since then the car will rev to about 1800 rpms back down to 800 rpms about three a four times over when I'm coming to a stop coasting in nuetral. I put the hose back on. what could be the cause?