some problems with my new mustang

I'm the proud owner of a 2000 v6 mustang auto with 58,000 miles on her. I've had the car 2 weeks and I'm having some idle/stumbling problems at low rpm. It all started when one night when I started my car and it died less than 1 mile from my house. It started and drove normal till I reached a small incline. It was cold 30 degree night, 1/4 tank of gas and I was starting from a red light when I lost power and stalled, i was able to restart it but it quickly died and wouldn't restart. I called AAA and the next day was going to have it towed to a garage when the tow truck arrived the driver took a large pipe and told me to crank the engine while he smacked the gas tank and sure enough it started right up! It stalled again but another hit and I was driving fine except when I stopped at a sign and the idle was erratic a little throttle kept it running smoothly at about 1000 rpm. I thought it might of been bad gas and put some drygas and a full tank of gas in and it has been running fine except for the occasional shudder at idle from a stop.

Any clue how to fix this problem? I purchased a new fuel filter but need to get the special ford tool to remove it I wish the guy at pep boys would of told me that. No check engine light even came on but I have a feeling the previous owner may have disabled it or may be burnt out? cause it never lights up even when starting the car or when my car suddenly died.