You say it ran good ... as in fine... for a couple days after the body lift, then BAM it starts this high idle thing?
Did you by chance disconnect the battery for some reason before the high idle issue?
I did a body lift and had the battery leads off for several hours to clean things up there at the same time. Upon start-up and for a few weeks, I had idling issues with the bII. ( However never a 2000 rpm high idle). I had, and still do have to a lesser extent, a fluxuating/searching idle on cold start-up. I also had and it's healed itself, an occasional, temporary, almost stall, low idle that recovered quickly.
I'm probably gonna use all the wrong terminology here but, I, ...thought, ... I, ... read, ... somewhere, :
the engine managment computer has default parameters in which it's given to define what values it's expected to
recieve from the various sensors on the truck. Similarly, devises who's purpose is to control the engine, like a Ilde Air Control valve, is designed to react to a signal sent
from the comuper in an exact...sort-of "calibrated" fashon.If all is not alright with one or more of these sensors or actuators, as in, sorta "out of calibration"... as opposed to, just plain "not working", the computer will with time adjust to the "skewed" value it's getting from the offending sensor(s) or adjust to the unexpected results it's getting from a actuator.
In plain words, it'll run better with time. If thats true, it explains whats happened to my truck because, while it's not perfect, it's much better.
This only applies IF you had removed power to the computer... and mayby it has to be for a significant amount of time. I don't know.
'Course, I also could be full of crap,
, because now, to get it started, the stinkin' thing always prefers two short cranking cycles, (where it fires right up on the second crank), as opposed to one long, like eight second, cranking cycle, , ( where it stumbles and "almost fires off" several times), before finally starting.
Tell me I ain't having fun with this truck.
Mayby the injectors are dirt..... dave
my 88 b2 is runnin about 2000 rpm and wont run any lower the only thing ive done aside from body lift (yes i redid the ground strap) is a hiflow cone filter it ran good for a couple days then bam low idle is 2000 rpm what did i forget (stupid 
computers)
