Have a 2001 ford focus zx3 2.0l dohc idles rough, high idle misfires.
Was told it could be the spark plugs needed replacing, so i went ahead and did a tune up. Changed all filters, spark plugs and cables, ignition coil pack and changed the oil about 2 weeks ago. But a couple of days before i did the tune up the serpentine belt snapped(it snapped while driving)so I replaced it and idler pulley. Then did the tune up. Still misfires and idles rough and high idle. Still no check engine light. What could it be?