Problem was at first annoying, then concern hightened by little or no engine speed when it did start. One occasion I had to start the car a dozen times then pull off the road when it ran badly. Check engine light on and off intermittently. Difficult to diagnose if not having problem at dealer. Computer upgrade of crank sensor did not solve problem. Concerned about safety of trying to work on highway and having engine speed limited. Very expensive repair for car with about 78,000 miles. Consistently had oil changes maintenance based on manufacturer's recommendations. Will not purchase another Hyundai vehicle.