87 Gt Idle Problems

I have a stock 1987 Ford mustang GT, only mods are under drive pulleys and electric fan. When I start the car in the morning and its cold the idle will go up to 1500rpm for a second and then drop to 1000 and then the idle will surge from 700-1200 until the car warms up, then once the car warms up the car idles high at around 1200 rpm, and if I pull the spout connector it goes down to 1000rpm. My timing is set 10 degrees.

Also I have tried checking TPS I am getting the right voltage, and also I tried disconnecting the IAC with the engine running and the engine shuts off, don't know if that's normal or not because when they recommend to try that they talk of the engine sputtering or smoothing out.

Update - Pulled some codes
ON KOEO got codes 54, 34 and under the stored codes I got 11
With KOER I got 98 then 54

karthief said:

I will add that the underdrive pullies cause charging and cooling problems and should be avoided on street driven stangs, I am also guessing you have a good tuneup and checked for broken, soft or hard/cracked vacuum lines

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ive been through the issues on the under drive pulleys causing charging and cooling problems which I don't actually have with everything I'm running on my car, I have a 130 amp alternator, 12in dual electric fans, a aftermarket 2row aluminum radiator and a 160F thermostat. Car has new distributor, cap, rotor, plugs, wires, ignition coil, fuel pump, fuel filter. I'm planning on replacing all my vacuum lines to try to get rid of any vacuum leaks even though I tried checking for leaks and found none. Also not sure if this is normal because I heard the EGR should have no vacuum at idle but mine had a very small bit of vacuum.