My cousin has a 1993 Suburban that has an idle problem. It will run for 30 seconds to 2 minutes, then die. The fuel pump is about a year old & the IAC was just replaced. I disconnected the vacuum line from the EGR valve & it made no difference. My cousin's wife says that it will run fine at speed, but it dies at idle (in neutral or in gear - makes no difference). What is the next thing to look at?? Throttle Position Sensor?? MAP Sensor?? Any input will be greatly appreciated. Thanks in advance.