Hey guys, New to the forum of course. But I am having a head scratcher of a time figuring out the cold tuning of this New carb. I picked up a Holley Street Avenger 870cfm for my truck. Current truck is an 89 chevy 2500 LD ext long box. I have a fresh built 496 under the hood currently. 10.76:1 compression ratio. Comp cams XE 268 grind 268/280 Duration 224/230 Duration @ .050. Have 781 heads with 2.19 intake valves and 1.720 exhaust. 60 over pistons and 6.385 rods. Intake is a GM cast iron 948. Timing is set at 10 Degrees advanced with a total at 3000 rpm of 20 degrees. I removed the Qjet 850 I had on it do to it needinbg bushings installed in the lower rods. It has recently dropped below freezing around the 0 degree Fahrenheit. Ill go out pump the gas twice with the ignition on to set the choke. Fires right up in about half a turn, rpms shoot up to the high idle numbers and drop off right away to hot idle. The truck idles for around 1 minute at 600 rpm and will stall out. My question is what am I missing on why it wont stay on the high idle? On a warm day it will drop rpm and slowly climb in rpm until its at the high idle range until I blip the throttle. Now since its cold it does not climb back up. Just looking for some input. Thanks in advance.