I own a 2003 GMC Sierra and this is my first car. It runs great and was taken care of by the previous owner who I know. The screen below my gauge cluster read change engine oil one day which I know is not that big of a deal. After about one or two days the check engine light came on and is on steady. The truck still runs fine and I have not yet changed the oil (it has only been two or three days since the change oil indicator appeared). My problem though is now the truck drips engine oil from near the drain plug and where the gasket would be. It only drips about once every couple of days but is this the reason my check engine light is on, or is it more serious? Should I spend the money to buy a new gasket when I change the oil myself or should I take it to the dealership before I try replacing the gasket?......My main concern is that I do not want to take it to the dealership and find out that it was the gasket that made the light appear because I am capable of fixing that myself for MUCH less money. Thankyou. 
