Q: Idles Fine. When Idled for 20 - 30 minutes will run fine. Sputters and tries to stall out when driving and accelerating when cold.
A: You have an air/fuel problem . Most likely it is a vacuum issue . The requirements for idle are much different than for under load driving . A soapy water mix sprayed on vacuum line hoses and connection points may show the problem , Look for the water to be sucked into the problem point . Also check for leaks around the intake manifold .