2000 Sable LS Premium rough idle, hesitation,

the above mentioned car exhibits all these symptoms and more. Codes 171/174 indicate lean mix left bank or whatever. I'm tired hearing about that shit; it seems they're not very accurate. It said possible causes were MAF sensor, upstream O2 sensors, and/or EGR sensor. So I replaced/cleaned all of the above to no avail. Car still ran bad. Funny thing is I also have an '02 Ford windstar minivan that did exact same thing with the same codes. I took that one to the shop and they replaced the coil pack and now it idles and runs like a champ but it cost me over three hundred dollars. That was the conventional coil pack. My Sable has the Coil Over Plug Ignition system and I would like to know if anyone out there has any experience with diagnosing the individual coils and how to replace them. Thanks! :screwy::banghead: