I can only suggest the obvious troubleshooting procedures; which any dealer or competent mechanic would check first. Return coil spring, binding in cable, stuck throttle body plate, etc. An air leak somewhere might cause slight increase in rpm. But again, I would think any good mechanic would be on those items.

Also there maybe some causal factorsassociated with the system that controls highidle at startup; but all of that is sensor and ECM controlled, and I do not know how you would check that. The idle control ciruits operate independently of the throttle plate opening.

Finally, make certain your cruise control is OFF.

Otherwise, until there areadditonal details or symptoms, thisis an enigma to me.