Car stutters while idling and driving. Changed all fluids, spark plugs, filters and such. No water in oil or oil in coolant. Change oil light has come on but no other lights have including check engine light. Took to a mechanic and still no change after lots of parts replaced such as alternator. Confused about what else it could be wrong. Is is electrical? And if so will resetting computer help? And if so, how do I reset the computer?