Ive been working on my f250 for some time now and it sat for a while before i got it started up and when i got it started it has a misfire and a high idle. i replaced the spark plugs and then started it up after and the truck ran great. now today i jumped a curb with it and right then it started the same misfire crap as before now like before it wont go past 35mph and the truck shakes real bad. does this sound like a loose wire? fuel injectors? any ideas are apreciated. thanks.

 

Sounds like a plug wire came off or your cap is loose. Hit a hard bump and it starts running rough. The easiest way in the world to find a plug wire shorting or loose wire causing a running problem is to just raise the hood and start it up, checking all around the plugs, wires, cap, etc. The key here is to do it at the right time and that is when it gets good and dark outside. You'll see the spark, I bet on it.