i got a hpi nitro mt and when i get it going good it just shuts down i dont noe wats wrong with it so any help please

glen

It's probably not tuned properly.
It's probably running lean - but it could be rich too, really hard to say with the little info you gave.
Go to youtube and type in "nitro tuning" and look for the 2 HPI tuning videos. They're done using a Savaage but tuning is the same no matter the brand, truck or engine.