I had some overheating issues about a month ago. I replaced the water pump, thermostat, and coolant. All Toyota parts including the coolant. Since then I did have one instance where the temp gauge creeped above normal, but it came back down immediately. I hadn’t considered the head gasket, I don’t see any leaks. Obviously it could still be going bad, just don’t see any oil in the driveway. Would a head gasket that isn’t leaking cause a cylinder to miss?