Ford Repair: Engine wont idle when breaks applied in drive, rush hour traffic, vacuum leak

Question
Hi I have a 1988 Fordf150 Lariat with a 351 cleveland in it and fuel injected. When I drive it and come to a stop at a intersection it wants to stall I have to quickly put it in neutral just so that it will idle properly. Reall pain in the but when in rush hour traffic. Any Idears?

Answer
first open hood and with running and listen for a hissing noise which would indicate a possible vacuum leak-if no noise-turn truck off and pull air inlet hoses off of throttle body and have someone push accelerator down while you look inside and see if they are dirty if they are-take some throttle body cleaner and a wire brush to clean it out-also pull idle motor off which is on side or top of throttle bore and clean it out also-put it back together and start it and run it may idle rough or stall a few times but will probably get better after running it.