My Acura TL 1999 2.3 suddenly stales with no warning. Starts up hesitantly.

 

Well no wonder. You've got a 2.3 liter engine when you should have a 3.2 liter engine. ;-)

Seriously, do a forum search for "stalls" or "stalling" and you'll find a ton of posts.

I had a stalling problem with my 1999 TL that turned out to be interference with another immobilizer-equipped Honda key on my keyring. I removed the Honda key and the stalling problems went away.

But there can be many causes for stall problems.

Bob