I disabled it using the method TDCRacing suggested. Initial results are promising. PTKR has dropped substantially. Either the EGR is faulty or dirty or the PCM just expects too much of it. My PTKR is near zero now, with occasional blips (which I'm told is unavoidable). I'll post before and after scans later.
Next, I'll be seeing if I can get into PE mode without the KR suddenly spiking.