I'm in the UK and bought a 3yr old CX30 GT Tech 2.0 Auto AWD skyactiv X 2020 model in March this year. It only had 7000mls on the clock, full service history and I bought it from an approved main dealership. By September I'd put on another 5000mls which is when I noticed i-stop wasn't activating and that on the Energy Flow Monitor the pistons icon was staying red all the time and not turning green while on the accelerator. Then the Amber Engine Malfunction warning came on, the car became sluggish especially up hills and the mpg went down, the warning told me to take it to a garage ASAP and to drive carefully. I took it to the dealership I bought it from, they told me i would be charged £139.50/hr for the diagnostic. After checking they told me it was a carbon build up on the fuel injectors? Asked what it meant and the answer was the injectors have to be pulled out, cleaned and reinstalled with new gaskets, the cost £1200.00. The car was sold with 12mths full Mazda warranty so I claimed but was told it wasn't covered because it was classed as a "cleaning of components" and not a failed component. I was angry and made my case, that I bought the car because the salesman raved about the low miles, the quality and reliability of Mazdas etc. They said they would contact Mazda warranties head office to see what could be done, they finally said they would pay 70% of the cost but I still had to pay £365.00. I renegotiated and spoke to the saleman who I dealt with, he spoke to his manager, the manager spoke to the Technical manager and they spoke to the top man at the dealership, he said the dealership would pay the £365.00 as a gesture of good will plus waive the diagnostic charge. I was happy but still concerned that a car with such low mileage could developed this problem, one thought being that just 7000mls in 3yrs might be the issue but the technician said they hadn't come across it before. I'm still concerned and feel it may be the car wasn't driven enough in the first 3yrs, also it could have something to do with the way the engine works with it's compression and ignition system but I genuinely don't know as I've never experienced this problem on any other car. In total the car has done 12k which is still low. Anybody out there with theories or experiences similar to mine please add your comments.