Id still make an appointment and have it looked at. exhaust gas leak detector kits work fine if the head gasket is blown bad enough. If its a situation where the issue occurs under load, youll never be able to safely reproduce the condition to accurately test it.Head Tester came in, I tested the coolant tank because I notices videos of people testing both the tank as well as the radiator. No signs of exhaust gas in the coolant. The oil is also normal so none there or signs of coolant in exhaust. Code has not come back since the gas treatment and Premium fuel. Really hoping that is all it was.