Yes these cars do like to shake when idling since they only have 3 cylinders. And they do create a lot of built up carbon for some reason. There is a simple solution to this though, run a can of Seafoam in the car every 5000 miles (which is how often you should be changing the oil). Put the Seafoam in 1000 miles before you change the oil to allow for it to really clean the engine. I usually find chunks of carbon in my oil when I change it.
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