I had to hang it up last night as the time was pushing midnight, and I hadn't completed the "search" yet.

I'll reveal what I've found so far. I have a spare throttle body with TPS and IAC valve attached to it. So, I swapped that out, after carefully setting that TPS first. I also swapped out the old spark plugs.

Interesting thing on the plugs, if someone can comment. The old ones were NGK's (I think), but they most definitely had "Denso" written on them. They had the flat center electrode. These new plugs I got from NAPA. They are NGK's, but not Denso. Most importantly, they have a v-shaped center electrode.

I haven't totally confirmed it yet, but I think the v-shaped ones cause slightly more of a miss. Now, I had mentioned earlier that there was a lot of "missing" in my testing. Keep in mind that I havn't driven this pickup since January, and it's been since early November since it was running properly. Plus, it's not a daily driver. I've only put 5000 miles on it in the last 1.5 years. Bottom line is that I do think I remember a miss being there before this head swap. Pretty sure of it actually. What I don't exactly remember was how severe it was. I've read from time to time that people have a miss like I do and can never quite figure it out. Well, I guess I'm one of them.

Now, after swapping the other TB out, along with the old Denso plugs, the engine ran like it's supposed to. Cold idle was around 1300, slowly tapering down to 1000 or so after warm-up. I can't get that idle down anymore for some reason, but at least it got that far.

So, I put the new plugs and TB back on, and she runs like crap again. I then swapped out the IAC valve only, and that's where I sit right now. It's about ready to fire up when I get back out there. I'm thinking it has to be in that IAC or the TPS, even though I thoroughly tested those TPS's and could find no fault in either one of them. The TB that I've been running is bored out (58mm), and it hasn't given me any trouble, so I'm skeptical that it is somehow the problem. However, I guess nothing will surprise me at this point.