Sudden starting problem

[JSPulliam21]

Last weekend I was at the cabin with some friends of mine. I pulled a few big logs out of the woods, and shut my truck off. I went back to move it about 30 min later, and it would not start. The LP would run and it would spin over, but would not fire. I pulled the codes with a Smarty and got a P1689 code. So, I unplugged the IP plug, checked it, plugged it back in, cleared the code, and it started back up. Later while driving down the road it coughed, missed, or hiccuped for half a second and was back to normal. I checked the codes when I got back, and P1689 was back. So, I turned the Comp off and drove it home with no problems. Sunday night I turned the Comp on for the drive back to school and had no problems. Yesterday I went out to start it after it had sat all night and it would not start. I did not have the Smarty so I assumed it was the same code. I wiggled the plug on the IP and it started just fine. Any ideas what in the world is going on? I am going home today, I hope, and need it to start.