I've got this problem and I can't find a fix for it at all. After start up the idle surges from 1200-1600 then the surges get smaller and smaller until it idles fine and steady at 750 after about a minute. Code 14 IACV is coming up. I have done the 2-wire iacv conversion and it has been working just fine until I put my turbo on.

I have no vacuum leaks,
no boost leaks,
tried a new chip,
tried a new ecu,
tried a new(used) iacv,
tried re-wiring the iacv wires
tried a different obd2b to obd1 conversion harness

The thing is I get absolutely no codes when I plug the stock p2p ecu back in. It only does this when I run the conversion harness and chipped ecu with uberdata basemap. The code 14 is always on and I can't get rid of it even by resetting the ecu.

My setup is a stock y7 block with y8 head, t3 60/48, log mani, dsm 450's, chipped p75.