if its starting with the fluid, ok there might be some sort of choke, but have you checked your fuel pressure, clogged filter, maybe your injiectors it is a 97, have you ever run any injuector cleaner, thru your fuel??? just some other ideas but being worse when cooler sounds like choke... just guessing here by what your saying, I've never even looked at a astro... maybe your Tbs === throttle body sensor. hope that helps ..
sevety9