'91 4-Runner cuts off....NEED HELP PLZ

Have a 1991 4-runner that will all of a sudden just die at idle after coming to a stop. Sometimes you can keep it idled up to prevent it. This does not happen all the time, maybe 2 or 3 times a week. Sometimes it starts right back, sometimes you gotta work with it to get it to start back. I also notice a hesitation when it gets ready to cut off. It has had just about everyhing in the fuel system checked or replaced, but nothing has helped. Any ideas?

Also, anyone know how to put the computer in disgnostic mode so it will flash trouble codes? I know on GM vehicles you can do it by juming pins on the OBD connector.

Thanks for any help or advice

also the trouble code it flashes is for VSS, could that really cause it to cut off?