Does the IAC being disconnected will give you lean mixture at full throttle (race condition)?
I know it works at Idle when engine is cold. I forgot to connect it back and went out to race and engine temp went up (225 F). Engine was dynoed with ignition problem and could not get it right. At race track it was found that the distributor was bad, but there was no time to check with a wideband. By saying this, another question comes out. Will a bad distributor cause a lean mixture?

 

No and no.

At WOT, your restriction is the valve area, port, and intake path. Opening another hole in front of all that will not force the engine to ingest any more air.

And an ignition deficiency would typically cause a rich mixture. UNLESS it's a complete misfire and you pump out a cylinder worth of unburned air. That can cause a lean reading...

 

Thks for your response. Definitely it answered my question. A bad distributor will give a rich mixture during dyno and because of, it was adjusted somehow lean to compensate for it and when I put the distributor then I had complete spark on all cylinders therefore lean mixture at WOT.