In May of 2019 I relocated to Denver from Tulsa. When I got here I had problems with the check engine light coming on and staying on. I would check it at O'Reilly's and it is always Cylinder 4 misfire. I changed the cylinder 4 plug and wire, no change. I then changed the cap and the coil block and all wires but it stayed on...for a while. Then one day it went off after a few weeks. I drove it to Tulsa, no problem. On the way back to Denver, half way across no mans land it came on again and stayed on till we reached Denver. It stayed on a few weeks more, then it went off and stayed off about a year. Here sometime last week it came back on. I checked it and again Cylinder 4 misfire. The light remains on since it came on. Is it really misfiring? What's UH da deal? Frustrated!!