So i just purchased a 2007 ford expedition.....the problem im having is when im cruising and i go to accelerate on the gas pedal, the truck starts bucking....couple people told me it might be a bad coil ??...it also did it from a dead stop when i stepped on the gas...anyone experience this or might know what is up...

 

It can be several things such as a vacuum leak, a weak fuel pump, a bad fuel regulator, or a bad throttle position sensor just to name a few. These are good starting points for diagnosing the issue. You'll have to start testing until something shows up as not good.