So a few days ago engine started ticking, on start up but would go away when the engine warmed up. (ticking seems to be from the top) would stumble some times until warm -- Cyl 6 Misfire code was thrown. Did seafoam, Drove about 50 miles, just did an oil change, some ticking then it went away. But then I noticed a sewing machine noise? coming from the passenger side (could the oil pump be failing?)