why is it shaking and hesitating when accelerating. on 2000 Ford Expedition

It shakes everytime you push on the gas, and quits when you don't. sometimes it will shake when sitting there. Idols higher than normal. running pretty rough now.

Asked by for the 2000 Ford Expedition
Sounds like you have a misfire problem. Here is an article about misfires to help explain what it is : http://repairpal.com/misfire-what-does-it-mean
1 more answer , 2 more comments
Replace all your coil packs with after market
did you mean after market like autozone coil paks and about how much are they
Go on Ebay and get an aftermarket set. I bought 8 coils for $57.00 (free shipping); bought my plugs locally and found a mechanic to install them for $45.00. My Exp. did the same thing...it wasn't burning all the fuel. Get them all replaced at the same time or it will throw the computor off.