1991 300E 4matic.

Car starts up cold and idles at 1k - 1.1k. As soon as it hits operating temp the idle shoots up to 1.9k - 2k. Disconnect icv and it hands out at 1100 when warm and ~500 - 600 idling in gear.

I think this started after I did a head gasket replacement, but I am not sure as the car sat for some time.
The air pump failed, so I removed it. I removed it and plugged the appropriate lines. While I was doing the head gasket I decided to delete the egr line, block the egr valve and plug the hole in the intake manifold.

Vacuum is at ~18 - 19 in-hg and is steady at idle (icv connected or disconnected)
Replaced idle control valve with a brand new one.
Fixed a few vac leaks around injectors.
4 prong temp sensor checks out against this
2 prong sensor does not read the same as 4 prong (not sure if it is supposed to)

Perhaps I was wrong, but I was pretty sure I could delete the egr stuff since I have seen many people block their egr valve. (We do not have inspections where I live)
What is left? The 2 prong temp sensor? The O2 sensor?

Other than the egr stuff I am at a loss.