1983 Ford Crown Victoria Ltd 5 0 Engine Taken 3 Shops They R Stomped Starts

i have a 1983 ltd Crown Victoria with a 5.0 engine. I have taken it to 3 shops and they r stomped. I starts up, runs and shuts down. when u start it up it runs but when u put it in drive or reverse,it shuts down. i replaced the throttle body, i replaced the torque converter . it still starts and then put in gear it shuts down again. if i hold the break and gas and put it in gear it will go. i can run it down the street with out the break ,it will run regular till i need to come to a light and slow down it shuts down. its got good fuel presure. i had the checked. please help if u can.