Can't diagnose my 2013 Ford Escape

My engine accelerates really fast upon a cold start. When warm it sometimes seems like it wants to stall at a long stoplight. I had the timing belt,waterpump, and serpentine belt changed as regular maintenance before this ever happened. The repair shop said take it to the dealer who said they can’t do anything until it throws a code. Repair shop shop says it is the throttle body and dealer should take care of it. I just want to know what is going on and get it fixed!

This statement is completely wrong. It shows me the dealer is incompetent and should be avoided at all costs – 'cause those are costs YOU will pay while they just throw parts at the problem hoping something will fix it.

You really need to find either a better Ford dealer or a better independent local shop. Expect to pay them for the time it takes to diagnose the problem as well as the fix. Ask your friends, family and neighbors for a good mechanic. Not a cheap mechanic, a good one.