no cranking- had it towed to the dealer ship and they can't find anything wrong with it- but it wouldnt' start- turnover - lights came on - seat would move but it wouldn't even crank to start- dealership after it sat for 60 min waiting for the tow truck it started right up.
Many factors can lead to the engine idle speed operation wave: mixed gas concentration, running resistance change, air inflow etc... Cold car? Cold car conditions possible, because the engine running resistance, speed off faster. If just cleaning the feast valve, or computer made clear fault memory, engine control system needs certain self learning process. So may the season valve reflect not too orientation (are self learning process) be caused by.
auto diagnostic tool-> www.hobd2.com