2010 @120k miles. Misfiring after spark plug replacement and sulfur smell?

Re-read my post #17 & emphasizing the last 4 words on sentence one.

 

I just recently went through this exact same thing. Misfire in cylinder 2 & 4. This misfire in 4 is caused by the EGR cooler being clogged with carbon. Coolant is not flowing through it, just around it, therefore the overheated gasses occasionally makes 4 misfire. Plenty of advice here on how to clean it properly (if you don't want to replace it). The misfire in 2 is caused by a bad head gasket. If you're losing any coolant, or if there's coolant in the oil, then you will need the head redone or even an engine replacement. If not, you can try your luck with a gasket sealant product- Bars Leak Carbon Fiber Head Seal worked for me.

 

I had the knocking sulfur odor when the egr valve was duck open. Have the cleaned the egr valve?

 

The only reason for a misfire in 2 (other than a bad ECU) is a bad head gasket. It isn't bad enough to really affect compression it seems, but it's bad enough to allow for the air/fuel mix to be disrupted it seems. From what I've read here, most people that have experienced a more catastrophic failure of the head gasket (meaning coolant loss into the combustion chambers) have all had cylinder 1 compromised. I can't recall if I mentioned here that I replaced the plugs, coil pack, and injectors as well, with the #2 misfire persistent afterwards.

Try the gasket sealant first- it's $30-40 cost compared to $1200+ for professional repair. It's about a month in and no troubles for me, and we drive in the mountains daily.