Based on everything you have mentioned, to me it sounds like one of three problems, the idle air control valve, throttle position sensor, or a fuel pressure issue. Please understand, it is hard when I am not there to experience the problem with you.
As far as fuel pressure, it is easy to check. The only thing you need is a pressure gauge. Most parts stores will lend or rent them to you.
Here is a video (how to) for checking both fuel pressure and the regulator. Please check both.
Friday, October 15th, 2010 AT 1:39 PM