Help idle problem

[Kamakaziracer89]

Well ever since i ran some throttle body cleaner through my 1990 240 its been idling at 1500rpm. I tried to adjust the idle as per the service manual but it still wouldn't drop down any lower. I checked for a vacuum leak and after pinching off all the hoses going into the intake i found that when i pinch off the air hose going from the idle air control Valve back to the Intake neck and and the idle drops back down to normal. I checked the duty cycle on Idle air control Solenoid and its with in the normal Range. So i replaced the idle air control solenoid today and when i fired it up it idled at about the same than the second time i started it up it shot up to 2000 and kinda fluctuated between 1800 and 240 and finally after a few minutes it dropped back down to 1500. Any ideas guys on what else i should check or what it could be? thanks in advanced

[Chukidori]

Maf....ECT...Check wiring harnesses....etc