I have a 2001 Dodge Ram that I hadn't driven much in the last month or so that has 31 K miles on it. When I took it to the store the other day the Service engine light came on. Any ideas about this. It is a 318 engine. Truck is not running hot or rough at all but I am worried a little.

Look here (http://www.allpar.com/fix/codes.html) or here (http://www.obdii.com/obdii.html) to learn how to find codes and what they mean.

MY '01 WITH a 318 in it had the check engine light come on at approx. 30,000 mi - it was the O2 sensor.......