[Lapister]

I would go back to the plug type you were running. I've had the same issue on another car, went from NGK to Bosch and resulted in power loss. Went back and have always stayed with oem plugs. It's probably a heat range issue. It's not too hard to get to them from below the car. Loosen hold down bolts for coil pack, pull out then replace plugs. If your car is running fine I would pass on Maf clean, different plugs as long as they are firing properly will not show Cels anyways. I really think your mechanic has good intentions but plugs are all different. You noticed a difference and it may be other drivers just never do.