I took my KIA Optima for service because it has an intermittent electrical problem that causes the air conditioner, radio, and cruise control to turn off for 1 second. This also causes my engine to stall or lose power momentarily. Also causing my car to jerk when the engine restarts. The dealer inspected the car and took it for a short drive on the freeway. They could not recreate the problem. My car still has the manufacture's warranty. The service technician tells me since they couldn't find a warranty related problem I should pay for the diagnostic fee. What should I do? Any ideas?