P0303 04 MAZDA 3 -

Question

recent head replace. ran fine for 2 days. hard start on day 3. misfire cylinder 3. changed plug, coil and fi. very rough running at idle, seems that engine smooths out about 2200 rpm. code was cleared but returns immediately

Answer 1

Hi there,

Since the code is coming right back it's possible there is a problem with the new coil, the wiring to the coil or some type of internal engine issue.