1989 245 manual 203K miles non-turbo

Holding the throttle open a "bit" the engine will rev up and cut out at about 1800rpm... it revs up and then cuts out, but then fires back up until it reaches that magic RPM! It will continue to cycle like that. Or when driven the car bucks until I upshift dropping the RPM.

Checked:
Fender mounted fuse.
Fuel relay.
throttle sw.
air control valve
both fuel pumps
plugs, wires and cap.
AMM
wires to the AC drier (3 green) are melted and cut, as well as the wires to the dash mounted AC control. I noticed these when searching for a vacume leak.

Diag code of 223, no check eng. light
When driven, a code of 234 with check eng light.

both can be cleared and repeated.

any ideas on what I'm missing would be greatly appreciated! The wiring between ICU and knock sensor seems to be ok, but no voltage at the sensor. Is it bad?


BTW what's the plastic piece tied to the battery tray? I'm fairly mechanical, but I couldn't figure that one out!