This just started about 2 weeks ago. When i first start the engine, it idles around 1600 rmp for about 2 minutes then slowly drops to around 1100 rpm, after the temp gauge starts to move, it drops to around 700-800 rpm. Before it would idle at 1300-1400 for 5-10 seconds then drop to 1100 to warm up. After it drops to 700-800, if I push on the brake pedal it pushes the idle to 1100-1200. I am thinking there is a small hole in the brake booster diaphragm that opens when the brake pedal is depressed, however the brake pedal doesn't feel hard because of the loss of vaccum. Any suggestions?