My very same car did this once or twice. Then all was well, and has not returned, since I did a BG Induction System service.
Pressure bleed-off would cause a hard start condition, but once the engine is started, there should be no noticable troubles.
Carbon build up on the valves and combustion chamber is a likely cause. Find a shop that does this service, it really is the best.
http://www.bgfindashop.com/bgservices/fuelair.htm