Yesterday I was driving the truck on the highway and it would jerk and vibrate bad every few minutes. I pulled over and opened the hood to see if there was anything obvious. The engine would idle normally and then all of a sudden jerk and rattle really bad for a few seconds. It sounded as though there was someone inside the engine banging on the valve cover with a hammer. I thought that it could be bad fuel or water in the fuel or something so I drained the water separater and started it back up. It did it one more time and hasn't done it since. The conditions were raining and the engine was fully warmed up. Another possibility that I thought of was a wet wire connection somewhere. What are your guy's thoughts on this? Thanks

 

Mine has 2 connections for the quad box. Both are on top of the engine behind the air horn. I think the map sensor and the rail sensor. When unplugged, one has a blue rubber seal the other orange.

My orange one has moisture in it or a bad wire some where, happens more on humid days, but when it comes looses or breaks connection it rattles worse than a 1st gen, spits and sputters. Usually if I shut the key off it starts up fine or if I keep moving it will also straighten out.

Mine is a 2005, I think the older ones maybe on the drivers side of the engine.

 

yeah thats probably it then. I'll probably dry them out and then weather proof them.

 

I thought my engine was missing once, but I popped the hood and there it was....

Sorry.... Little humor there...... Very little.......