2003 Chevy Malibu High idle

I just removed my coolant sensor gauge and had to remove the throtle to get to it. It was leaking and I wanted to re seal it. Once I resealed it my engine was at a really low idle. But I had to leave for work. It was sputturing to stay running. I started to drive and my brakes wouldnt work very well. They were very hard. I drove about ten miles and now my brakes work but my car is idling at about 4k. What should I do?