When l start my engine l have to push on the gas pedal to get it started but as soon as l take my foot off the pedal the engine stalls out and now my exhaust is making noises that l never heard before. The engine is acting differently to when im pushing the gas and keep it at a steady 2 rpm it jumps up to 3 or 4 rpms then goes back down and keeps doing it any suggestions of what it might be? Thanks in advanced

Leaking vacuum hose. Take it in for a tune up. They will fix you up.