2007 XC90 random misfires at start up. mostly cylinder 6.. compression is good. I changed plugs, I changed coils. I changed pcv diaphragm I changed intake manifold gasket I blew smoke to look for vacuum leak. I swapped the cam sensors ..I cleaned the mass air flow sensor I changed the fuel rail sensor WHAT THE FREAK PLEASE HELP I am lost.. added info i am having bank 1 sensor 2 post cat sensor issues at times..working just weird readout..HELP PLEASE.

 

two other thoughts 1) wire harness to the coils 2) fuel injector on #6 may be leaking (leaving a small amount of extra gas in the cylinder for the next start up) Any oil consumption or coolant loss going on?

 

I pulled the fuel rail. Checked the spray pattern on the injectors. It looked fine. No visible leaks what is your thought process on the coolant?

 

I pulled the fuel rail. Checked the spray pattern on the injectors. It looked fine. No visible leaks what is your thought process on the coolant?

 

The misfires are only at start up. Even when the engine is warm. I was thinking maybe a small crack/leak in the head gasket that seals itself when the engine is hot. But I still get the misfire when starting with a hot engine