my friend has a 1996 automatic camry and it always runs great but all of a sudden today it wouldnt idle, if he gives it gas it will stay running but as soon as he lets go it would stall. so i told him to stay on the gas for like 5min around 4k rpm and then see if it worked, and after 5 tries it did, the car didnt stall. so wtf is going on, im thinking bad IAC or EGR valve? how can i check to be sure?