'91 Olds 98 regency elite engine timing off

I just bought this car a month ago. ~160k mi. After driving ~200 mi, the next day the car had trouble starting and would periodically stall. My fuel economy dropped from ~24mpg to ~16mpg. When I listen to the engine running, i can hear slight pings coming from it at irratic intervals. the exhaust sounds like a boat that is in water. Very sputtery. I checked the wires, and all were connected. That is about it. I took it to a Firestone today and they tell me that I have a bad ignition coil which has also messed up the ignition module. In addition, they recommend new plugs and wires, since the "resistance" in the wires may have been the cause of this. They want $850 for parts and labor for the wires, plugs, coil and module.

First of all, if my coil was bad, then wouldn't the car not fire at all?

Second, does this price seem fair?

Third does their diagnosis fit my symptoms?

Fourth is this a relatively easy job that a not so good mechanic (me) could do?

Finally any ideas relating to my situation would be appreaciated.

Thanks

If the ignition coil is bad, you cshould be able to identify it when the engine is running by removing and reinstalling the wires one at a time. You should notice that if there is one dead cylinder there should be a second, as each pack controls 2 cylinders. If you can identify this to be the problem, then you can probably skip the rest of the stuff. If it doesn't seem to be the problem, you might need to change the icm. I don't see where the wires and plugs would be at fault if you just replaced them, unless you either bought the wrong ones or you got some with inferior quality. Most wires are OEM size or larger so resistance shouldn't be a problem. Reguardless, $850 is a bit extreme for a job you can do yourself for about half the price or less.Often you can get a decent one at the junknyard for pennies on the dollar.