So my 93 has a weird issue where if you're sitting idling and rev the engine the idle will jump up and down between 1500-2000rpm till the fans kick on and then it'll settle down to 875rpm.

This also happens when driving. If you just push in the clutch when coming to a stop the idle will start bouncing from 1500-2000rpm. If you down shift and get the rpms below 1200 it'll idle normally.

New VDO idle valve and no vacuum leaks.

Any ideas?