All 4 cylinders are misfiring

Well thing is the codes are telling me all cylinders are misfiring where should I start with this cause after i changed spark plugs and I started it bug White cloud of smoke came out and it stunk it's been smoking alot before it starting misfiring but when it got warm I'm talking like well after it got warm it would quit smoking and I thought all coils or plugs or injectors would go all at once what about wire harness but then again after this smoking I'm thinking cat converter is bad this just got my brain racking cause it could be so many different things what you think?

Well it got a mass flow sensor I looked it up online I'll look at my car in morning also and check it out do you think I should start there?

Ok I'm gonna look into my head gasket a little more today my coolant jug is on low level but my radiator is full do you think my mass flow sensor I'm gonna look into both of these would it leak oil around my head if gasket is bad???

Ok I am going to do that thank you very very much you was very helpful when I do this I will let you know what's going on my car was smoking alot for a month straight then it would quit then start smoking when it was cold and couple time when I started it a big cloud of white smoke came out and smelled like burnt oil

I'm smelled my oil dip stick and it smells like gas so would that be injectors???

Ahh ok I understand so should I test the pressure my cousin has a tester and I'm gonna pick him up and we're gonna test it but if it is not the head gasket what else could it be pumping gas into oil when I start it a big cloud of white smoke comes out and smells like burnt oil/gas idk what else would do that though I don't wanna drive it in case it gets worse and blows or damage something else right if I drive it there's a big chance of a t messing something else up or something right??

Would bad fuel injectors do this but I don't understand why all cylinders are misfiring it's very unlikely all jectors would go all at once but what I don't get is I drove it home the night before from work and it was fine nothing wrong with it then when I got I it the next day and started it was misfiring is there any reason why or what cause this

Well it was smoking alot for month or 2 the check engine light came on and went off 2 days later then this happen the smoke did stink and I think coolant went down in my jug cause it was at the L line And now it's inch below the L line so what is the best idea test the pressure?

Ok thank you very much for your help you definitely helped me alot I'll let you Kno if I found the problem or didn't