I feel your pain, one and all. Luckily my 1.6 CVT was bought from a family friends garage so all work done has been paid by them. They are letting me use the car until they can find a suitable, manual, replacement. I have had EGR valves changed, Turbo boost pressure sensors replaced, wiring joints cleaned and waterproofed and they paid for a tuning box to be fitted to get rid of the acceleration 'dead zone'. The tuning box has improved mpg and performance, but not cured the 1600 - 2000 rpm stutter, it just happens at 1800 - 2200 rpm instead now! They have come to the conclusion that it is just an incompatible engine and gearbox combination. I have read about solenoids shorting out, but that was found, by chance at 2am in the morning by the owner. The fault occured while driving home one night down an unlit road, he left the car running and popped the bonnet not expecting to find anything, just out of frustration. Anyway, he reported seeing some sparking (he doesn't pinpoint where though) to the garage breakdown guy and they replace and shield the solenoids. Hey presto, the problem was cured! Could be an old wives tale but sounds plausable to me. You just need to find a garage that is willing to work at 2am with the lights off when your C-Max starts to do it's thing, pfffft.