As the title states I have a 1991 f250 with the 460.
after doing plugs, cap and rotor the other week, it drove fine and then died after 20 miles. Long story short I chased through and replaced TFI(fender mounted for this model), distributor, and finally tracked down my issue to the ignition coil. My tachometer wire(spliced into the negative signal wire for the coil) had melted and grounded against the exhaust. Replaced the coil and truck started up.

on to the current problem, after setting base timing at 10 degrees, I’m getting significant spark knock under load and idling at 900 rpm regardless of cold start or at temp. Unplugging the iac has no effect on idle, however plugging it back in gives a small temporary surge in idle which to me indicates it’s functioning in some manner. However when I unplug the SPOUT connector, the engine drops to its base idle of 550-600. It drives fine at this base idle but obviously doesn’t adjust timing leaving me with no power past 2400. With spout plugged in I’m reading 32 degrees at idle, and it slowly works down to about 27 or so.

none of these issues were present prior to ignition work which leans me towards it being a new variable. Anyone have anything similar?

to summarize need help fixing spark knock, high idle, and high timing after ignition work. Base timing is correct, base idle seems correct, iac seems to respond however the engine seems to control idle via timing instead of airflow.