RPM Drop in test mode (Te1 and E1 jumpered)

[mk3777]

I need some Toyota expert help,
On my 93 Corolla
When I connect the Te1 and E1 connectors together the RPM revs up and after few seconds drops below normal RPM, to the point that the car almost stalls.
When reading instructions on testing Idle Air Control in my manual it says that the rpm shoulg go up and return to normal idle in few seconds.
I found this while checking my O2 sensor, ( its working fine, I got 12 counts in 10 s at 2500RPM).
My reasoning is that in test mode the idle increase and timing advance are not
functioning, but why is it not at 700rpm as it should?
The car was fully warmed-up.
I want to check ignition timing but the car is supposed to be exactly at 700rpm in order to check the timing.
Would it be OK to rev up the motor to 700 RPM and check the timing that way?
I also checked the resistance between the center and the two outer pins of the IAC valve and they were both around 24 ohms which is normal.


Any help on this would be appreciated.
I know there are some really good experts on these formus.

93 Corolla, MT, no AC.
Car had last tune-up in the fall with replaced plugs air filter and distributor cap and rotor.

thanks in advance
Mike