Rough idle - Hard starts - Cold starts

[SoCalSlaughter]

Always something with this truck.. haha Well the truck is a 1990 Chevy V2500 4X4 Suburban, 350 tbi. The truck recently has been having a problem during cold starts. Go to crank and motor will turn and it will try to run, but stumble and die. It will only run if I hold the gas slightly. After holding the gas for awhile til it starts to warm up, I can then let off the gas and it will stay running on its own. Also, once it is warmed up, and I go to the store, or get gas, and go to restart the truck, it will turn over and run just fine, but starts up with a low idle, about 500 rpm. Once I throttle it the idle will come back up to around 700 rpm. Put the truck in park after its warmed up and the idle will be around 1100 rpm. I also noticed a drop in gas mileage. ALSO! lol I notice when the truck is started cold, it has a slight miss. I can hear a pop or puff from the exhaust every few seconds until it warms up then seems to run better. Ive already swapped out a IAC unit, reset computer, sprayed carb cleaner around tbi and intake. Thanks!!