2006 Ford Explorer

I was driving my Explorer and all the sudden the wrench ligh came on the gas petal would de-press but not really do anything. When I stopped the RPM's were bouncing up and down. I turned the ignition off and restarted the truck. It restarted with no problems and the light was gone. I drove it for about 3 miles and accelorated to 45 MPH when the wrench light came back on the truck was chugging and not responding to the gas petal again. This time the engine light came on and stayed on. I restarted it again and decided to turn around. With the restart this time the wrench light went off but the engine light stayed on. As I started up the over pass to my home the wrench light came back on and did not want to respond to the gas petal yet again. The RPM's were again bouncing up and down and the truck was struggling and chugging severlly. What could this be?