Trouble shifting into gear and shutting off?

1997 Chevy Blazer mileage: 106,000. For the last 6 months I have been having trouble putting it into gear and dying or having to start it 3 times keeping my foot on the gas and on the brake at the same time to prevent it from dying. Then at times when I am turning a corner it will die. It always restarts eventually but it’s dying more and more frequent. I have taken it to a mechanic and they have changed spark plugs, put in a new fuel filter, and a PCV valve. They have removed and cleaned throttle body and replace the thermostat and seal. That’s what’s on the bill anyway. I am going to take it to a different shop but would like to act like I have a clue this time.