I had my car in a garage for couple of weeks because of the bad weather in Chicago. Few days ago I decided to take it for a spin and the car started just fine. I drove for ten mins and stopped by a store and when i got back the car kept cranking but no start. I tried several times before it started. As soon as the car started I got a CHECK ENGINE light. Few more stops after the car kept starting great and the check engine light went off. Today same story car starts just fine when cold and after ten mins of driving and 20 mins before trying to start the engine, the car just kept cranking but still no start. Check Engine went ON again and the car seemed fine all day with starting after the second start. What could be the problem? I had the same gas in the tank for about a months and a half( could that be the problem)?. Today I added some Seafoam Fuel Additive and hopefully that will fix the problem.

Any suggestions?????????

04 Xfire Coupe
put only 93 Shell ever since i bought the car
Replaced the fuel filter last summer
replaced the air filters 1 year ago
changed oil last summer