I have a 2001 Audi A4 Quattro, 4 cylinder turbo. Recently, when my car has been running for some time, and I stop it, I am having problems starting it again. The car will "click", but the engine won't start. I recently put a new battery in, so it is not the battery.

I took it to the Audi Dealership, and they stated it could either be the coolant sensor that is causing this ($128.00 repair) or the throttle body ($640.00 repair) based upon the error codes.

Any ideas which of these two is the likely culprit?

Thanks for any help/insight you can provide!