Hello all. I have a 2016 XC60 T6 R-Design with about 34,000 miles. I bought it in January 2022 and about three months in my check engine light came on. Service at local independent shop reports they replaced the oil trap, spark plugs, and ignition coils. The vehicle continues to have the same issue and has been back for service 4 more times for the same issues. Last time I stopped at an auto parts store to have the codes checked, and cylinders 1 and 4 were misfiring. It seems the shop continues to replace the coils, not sure why, and doesn't seem to offer any other solution as to why this problem continues to happen. Sometimes the light comes on the next day after service. Sometimes it's a few days. One time it was a few weeks before problem occurred again. Is there something my mechanic could be missing?

 

what fuel grade do you run (drop in a premium brand 93 for your next fill if you are not doing so already)? Are you consuming any coolant? did the tech test for fuel pressure? PS - Usually the process for testing coils is to swap coils between a good cylinder and a bad ie if you have a cylinder 1 misfire, swap coils between 1 and 2. If the misfire remains on 1, its not the coil.