My car starts then dies even if I rev it up it just dies.

on the backside of the throttle body there is a black box make sure all the connectors are tight.this is what tells the ecm [computer] where the idle is.if the connectors are tight then loosen the hold down bolt and move the box down a little not too much and see if it will idle. then move it upwards a liitle higher than it was before and see what the idle does.be sure to give it a few minutes to let the computer have time to get the signals.