We had the timing belt changed at approx 33,000 miles (which the dealership caught while still under warrantee). Within a few months, the car started backfiring with acceleration. By spring the issue had increased in frequency and brought it in. The dealership cleaned it out using the walnut shell process (see previous complaint) and been good ever since, but, occasionally feel like I hear an occasional little 'backfire' which I recently informed the dealership. His explanation was that I need to drive the car at a higher RPM's to BLOW the carbon out. Hopefully this will remedy the problem😬😬😬

Carbon buildup in the engine (second occurrence) meant that the car had to be in the shop for a few days. They cleaned it with a "walnut shell blasting machine" that they said would be better and last longer than the previous "manual" carbon cleaning. Tried to blame it on bad gas (I only ever used top shelf premium, as the car requires). Was told that this was an unresolved and problematic engineering issue and that there was no permanent fix for it-- that I could basically expect it to reoccur every 15-20k miles.