Engine shaking at slight throttle

[Camo Ranger]

So, this morning I get off the highway and stop at a set of lights. The truck felt like it was running a little rough, but nothing that caused me any alarm. Then when I go to take off from the light the truck starts to shake something terrible. However, once I got it up past about 2000 RPM, the shaking started to lessen until it stopped somewhere before 2500 RPM. Then once I downshift into the next gear, and the RPM's drop, the shaking starts again. The truck kept doing this all the way to work and then again all the way home. As long as I keep the RPM's up above 2500 you wouldn't even know that anything is wrong.

When I popped the hood, I didn't see anything out of place. The truck isn't bogging down noticeably and the cat isnt making any popping sounds to suggest a rich fuel mixture. When I have the truck in nuetral and give it some throttle, the engine shakes quite a bit. It isn't throwing any codes either. It had new plugs and wires about two years ago (30,000 miles).

Anyone have any ideas?

 

[red93terror]

sounds like a miss due to a partially fouled plug or maybe a frayed plug wire. could be a bad coil pack or a clogged injector also.

 

[Camo Ranger]

Just wanted to close out this thread. Turned out to be a frayed spark plug wire. Didn't notice it because it was on part of the wire that sits between the engine and the fire wall. It's only a small hole too, probably not even a 1/4 in long. So the wire must have grounded itself causing the cylinder not to fire. Wish I had noticed it before I went and spent money to replace all the plugs though...