Changed MAF and cleaned ETM, not exactly fixed. Help?

[s80inWV]

1999 S80 NA model. ~200k miles, all routine maintenance has been done. If you don't want to read the long description, the short version is that I cleaned the ETM and changed the MAF and a portion of my problem persists, could it be spark?

The issues I had been getting were that right around ~60-70mph, especially while going up a mountain, especially with the a/c on, especially especially when its raining outside, I get a hesitation. RPM's done seem to change, it just appears to lose thrust for a second and then it's back. Cruise intermittently deciding to fail then come back on. I read the sticky here about MAF/ETM. I'd never had the hunting at idle issue or any of the other issues, save for that hesitation and the cruise control.

It's worth noting that about 2000 miles ago I did a course of air intake cleaner, which I wound up spraying into the intake BEFORE the MAF without thinking. I BELIEVE the issues started after this but I'm not sure. It barfed out a lot of gross smoke for about a minute, then ran fine and then had a lot more power/response, it's been really this late summer that the issues have really started.

I let my buddy borrow the car for the last week after his died (I've only put like 6k miles on it this year, I usually use my motorcycle), he ran through an entire tank of gas in a week but reported no issues. I got it back night before last, got in it yesterday morning, and it was doing the hunt at idle thing, bouncing between ~500rpm and 1500, very rough idle, power browning out while it tried to stay on.

Last night I replaced the MAF and popped off the ETM and gave it a nice cleaning. It really wasn't what I would consider to be bad. It's got the italian module in it, whatever it is with the two names that both start with M.

Got it back together, started it up, and it was ROUGH. I gave it some gas, and after about 30 seconds it was smooth. No bouncing, no issues. I took it for a short easy drive then took it to the interstate. No hesitation (but it doesn't always happen), throttle response seemed improved but that might be placebo. Took it home and parked it.

This morning, just for fun, I started it again. Super rough, actually stalled once but started right back up. ~30 seconds then smooth and fine.

As I surf around, I'm seeing other people with this issue and while some folks get it after a replacement w/o flash---I didn't do a replacement. I'm thinking now I have a spark issue---plugs/packs? I changed them when I first got the car about 10k ago, noticed then that one pack appeared a little wonky.

I've had a CEL for downstream 02 sensor for a long time, it was off when I put the battery back on last night and didn't come back on. This AM it's back on but didn't have time to scan before I left for work, I'll do that tonight and also probably pull some plugs to have a look. I've also got one SUPER noisy injector, but everything I've read says this is super common.

Any input is much obliged.

[Ozark Lee]

I'm going to go ahead and cross post this in the S80 forum where you will get a bit more attention. Since the ETM recall the Don's ETM Room forum is a bit orphaned.