Our 2012 Q5 has 91k miles on it and we keep it in tip-top shape. The past 3 months we continue to have an intermittent issue where the car will periodically do a crank-no start. We have to give it gas while trying to start and then it eventually starts. This may happen once every 20 - 30 starts. We took it to the dealer and it started fine for them and produced no error codes. The only correlation we could find was it seems to happen more after we fill up the gas tank. So we make sure to use Chevron or QT and only user Super 93. So far this issues has not left us stranded but it's more a nuisance and we feel there may be a larger underlying issue. The only major recent change since the problem started was we had an oil leak fixed and water pump replaced. While the covers were off, we had them do a carbon buildup cleanup. Shortly after that servicing, the problem started. Is it possible this is a timing belt issue?