Took to shop for oil change; when I drove back home, car is misfiring and check engine electrical system is on. Ran codes and got 300, 304 and 308. Changed plugs on those two cyclinders and one new coil #4. Switched around coils in other cyclinders. No codes but engine misfiring between 400 and 800...Could this be a crankshaft sensor issue? Starts with no problem