I’ve got a 2005 LLY Duramax, has an aftermarket air intake, had the muffler removed but kept the cat. Other than that the truck is all stock. Autozone said EGR Valve, I’m not sure. Truck was fine until we just had a heat wave and when I went to start it, glow plug light stayed on longer than normal and idle jumped to 700 right after it startw. Any thoughts on what it could be to prevent me replacing an eve valve. Had issues in the past with my EGR on my LB7, not wanting to do it again. Please help! Thanks!