Well... I think I may have this problem licked. I spent some more time with it last night and think I made some progress. I have only driven the truck twenty or thirty miles, though, so I'm not counting my chicks just yet.

However, the stumble that was present at the 2000 RPM mark appears to be gone, there is more get-up when I hit the gas pedal, and the check engine light isn't on yet.

However, I take it on a cross-country trip (Denver to Vegas in one day - with a five-year-old and a nine-year-old - wish me luck!), so that will be the acid test.

'98 Rodeo, Ranchos, OME 912s, General Grabber AT2 265/70/16s on steelies, Superwinch hubs, G80 code, Pioneer HU... two car seats and cracker crumbs.
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Illegitimus non carborundum.
Educatio est omnium efficacissima forma rebellionis.