Accelerator goes out on 2001 Nissan Altima

This has happened to me half a dozen times. After driving the car for about 45 min, while driving about 60 mps, my dash board controls bottom (except for the speedometer, which gets stuck at the speed I was driving) and the accelerator stops responding. If I take my foot off the petal, then put my foot back on, acceleration kicks in for a split second, then stops responding. Once I pull over and come to almost a complete stop, then my dash board controls kick back in, and the accelerator functions as normal. This whole time, the idle has been normal, so it doesn’t sound like an engine problem.

I took it to my mechanic, and they were perplexed. They replaced the ground wire thinking that might be it, but it didn’t fix the problem.

Anyone have any idea of what might be causing this?