please help

[n/a 2 turbo]

my engine idles pretty good but every 10 seconds or so it sounds like it misses an the rpm's drop a little, and when i accelerate the temp. gauge freaks out, an the engine runs rough. now by this point it usually stalls an when i try to start it again the temp. gauge goes all the way to hot an engine wont start. i checked the temp sensor an it works fine .. does anyone know how to fix this? also most of the time the engine runs an idles perfect doesn't missfire or anything