Can't help with specifics, but certainly any unmetered air leak will cause idle speed to increase - replace any doubtful hoses in the air intake or vacuum system. Use oem - airflow dynamics can change reaction time of vacuum-operated components, affecting speed of operation, if different diameter, length, or material of tubing is used.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7