Need Some Assistance w/ Problem

[McCauleyWB]

Short back story:
The car has been running well without issue. I was on the freeway a few days ago when it suddenly started misfiring severely and went completely dead. I managed to coast over 3 lanes of traffic and get safely to the shoulder. When turning the key to on again, the tach started jumping around and made a mechanical whining sound. I was on my way to work and couldn't look at it immediately so I had it towed back to my house. Fortunately, it started right up and I was able to get it in to the garage.

Jumping to today:
I hooked up the Scanmaster and took it out for a test drive. It didn't feel as strong as it should and had a high "choppy idle." The Scanmaster showed codes 16, 36, and 42. I believe a "MAF signal too high" also displayed when keeping a consistent RPM too. 16 and 36 aren't even in the manual for the device and I have no idea what they mean. Code 42 says "EST circuit failure. Bad ignition module. Bad ground." I figured as much with the bad ground and found the threading at the end of the battery cable (ground side) was getting stripped. I made a trip to the junkyard and replaced it with a good one. The car runs better now. It does not break up / die, but doesn't feel right either. It could be mental I suppose. I sometimes have to drive 70 miles a day for work and can't chance another breakdown. Finding it similar to LT1*FUN and Cross' post (in the same thread) a couple threads down, I will likely check out the suggestions already discussed there too. Does anyone know why the Scanmaster would show the first two codes, or what it could mean though?

Thanks.

EDIT: So the first two codes were not in the manual that I received with the unit, but I found a resource online that shows the following:
16 - OptiSpark low resolution pulse not found
36 - OptiSpark high resolution signal faulty
42 - Ignition control circuit, short or grounded

I have gone through a bad Opti twice before, but had entirely different problems at the time. Plus, it most recent Opti is fairly new. I have an inkling something else is wrong. Ideas?