I have a 98 GT with a quad 4 ld9, When its cold it idles perfectly at 900 rpm and when the temp goes up to 90~ degrees the idle slows right down, barely running. I drive a standard so I have to have it idleing at 900 rpms, so it dont stall at stop signs. Tell me whats up. I tried 4 idle control valves and same result. I DONT KNO HELP ME!! Please