Hello all. New to the forum. I just bought a 1973 450 SL. It looks and runs great, but has one small problem. I checked the archives, but couldn't really solve the problem. The car starts up immediately when cold and idles fine. However, after about a minute the idle begins to oscilllate up and down, up and down in large rpm swings. After about 45 seconds of this, everything is fine. The car runs fine once warmed up. Someone below mentioned a device on the passenger firewall, but couldn't remember the name. If anyone can help, I would appreciate it. I'd like to get this fixed this weekend.