A little after Christmas my check engine light came on. Taking it to a mechanic it was a P0303 error. They replaced the spark plugs and Ign/coil module. From there the check engine light randomly turned on and off rarely until about two weeks ago where it seemed to get in this cycle of turning off and on. It has always been for the same error. I took it back to the same mechanics and they replaced the 3 cylinder spark plug again. The check engine light just came back on today. What else could really be causing this and how much is it going to cost to fix?
As a further note even with the check engine light on I haven’t noticed a difference in how the car has been driving. Before/after the repair feels the same.