136k miles
plugs, boots and springs 10k ago
always run top tier fuel.

independent changed my oil but used 5w30 for the first time. Stomped on it tonight (it is -1* F here in central NY and engine was coldish), CEL flashed like six times and went on.

hit the on ramp and stomped on her and it flashed again.

P0300 and no other codes.

runs fine.

read a lot tonight about it.

is the change in viscosity just a coincidence? I have always run 5w20.

 

I wouldn't think engine oil viscosity change could cause a misfire. Your new oil still has the same fairly good cold temperature viscosity. Even if the oil change from synthetic to non synthetic occurs, I wouldn't think that can cause a misfire. I am no engineer so don't listen to me. Extreme cold can cause problems, maybe it was something else. Hopefully it was only related to the cold and nothing worse. I think this is worth investigating further. I had a couple of times my Expedition with 3.5 EB gave that same pattern of CEL during extreme cold and it went away and never showed any problems that I saw. I used to start needing to replace coils around 80k, so it could have been related but I didn't know it. My F150s with 5.0 never did this but they weren't daily drivers. I also often had the factory shocks feel like they had no damper when extremely cold. -26 at my house last night a little northeast of CNY.

 

Interestingly, I have not been able to duplicate it.

 

Now P0305. So I know where to start.

Programmed back to stock.

 

Doesn’t seem like a coincidence. The variable valve timing operates on oil pressure to advance timing of the camshaft. I’d revert back to 5W20 and see if it goes away.

 

Agreed. For now just taking it easy.