ltnate3 it could very well be coil pack related but I would also investigate the throttle position sensor. Most of the cars I have owned, have at some point have been help by the replacement of the TPS. The TPS is a mechanical potentiometer that does over time degrade. Being that you mentioned the hesitation is at 50, it’s likely in your driving patterns, you drive at that speed frequently or pass by that throttle position. You can connect a voltmeter to the TPS on the Ohm scale (analog meter would be easier to use) and very slowly, manually open the throttle with the engine off and the TPS disconnected and watch for any extreme needle movements indicating a “bad” spot on the TPS. The TPS unit is not expensive or difficult to replace. Just a thought.