How to flush the cooling system, after using blue devil head gasket solution

This may be your issue as it can clog up your system but check out these videos that we have on this product.

https://www.youtube.com/watch?v=Xi41RFMP8Ow

https://www.youtube.com/watch?v=iuEVLFEF0AM

If this clogged the system, then you will most likely need to replace items starting with the thermostat then flush the rest.

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

Once you flush it you will need to check the heater core hoses and make sure the temperature is equal when the heat is on high to make sure it is not restricted.

Please run through this info and let us know what questions you have.

Once you cure all this, we can tackle the misfire as I am not sure that is related to the coolant issue. So, if it is still there then we can figure that out as well.

Thanks