My car tries to turns over and then quickly shuts off. The shop said the throttle body needs to be replaced?

because the linkage is not adjustable and it will be a $1000. I'm reading it's very rare that need to be replaced and they can't figure what else might be wrong until they fix it.$$ ugh. If I push on the gas peddle it stays running. Anyone have any ideas what might be happening. I think I"m taking to a different mechanic. Help!!