I don't know much about cars and I need your help.
I bought a second hand Mitshubishi Galant and I only have 72 hrs to return it back to the dealer if I'm not satisfied with it.

Here's my problem...
I was driving my car when the "check engine" light went on.
I brought it to a mechanic and he checked what the problem was buy connecting a device(di ko nga alam kung saan nya ito kinabit sa car)and he said that the code showed that there is an IDLING PROBLEM. Magclose na sya ng shop kaya wala nang time to further check on the problem.

I really like the features on the car but I would want to know if IDLING is a serious problem and if it will cost a lot to fix it.

THANKS IN ADVANCE FOR YOUT ADVICE