Brake booster? on 2001 Dodge Neon

My car has been idleing higher than normal when in park. I took it to the shop they seemed lost and were fixing a needle in a haystack. They fixed the hose brake, valve brake, and grommett, now say need to fix brake booster, will cost 500 diollars.Is this what is really wrong?

1 answer
It is very easy to disconnect the brake booster from the system by disconnecting and plugging the vacuum hose that goes to the booster. I recommend doing this and if the problem goes away, that would be a good verification that the booster is bad.