EGR gunk is probably the culpright if DI engines do indeed still have this EVIL technology. I hate what EGR systems to the intake tracts of our vehicles. There has to be a better way.
The back of the valve heads should be mirror polished (not swirl polished)from the factory on DI engines that do not get the fuel spray wash.
Every new direction has its compromise
The back of the valve heads should be mirror polished (not swirl polished)from the factory on DI engines that do not get the fuel spray wash.
Every new direction has its compromise