I have a 2005 Ram quad cab 4.7L with about 30,300 miles. My engine light came on last weekend for a couple of days and then turned off. It recently came back on yesterday. I know its time for a tune up for the spark plugs, and PCV. But I was curious to know if there might be something else causing the engine light to come on before I change out the spark plugs and PCV? Also, is there anything else I should change out for this 30,000 mile tune up?