IAC VALVE

MD9 (TH125C) DTC P0507 idle higher than recommended tested with DVM cleaned IAC and inside throttle body. Checked pintle distance reinstalled and drive-cycled at operation temperature no good. Installed new aftermarket VLV after checking pintle distance at spec of 1-1/8" new one was at 1-3/16" tried to retract pintle to no avail by instructions. Installed it cleared DTC and drive-cycled at operation temperature and more for PCM reset. Idle still too high 1200's- hi 1300's. Drove it over and days idle dropped to lo 800's- hi 900's still too high. Also when driving and decelerate to a stop rpm takes 3-4 seconds to drop back to 800-900's. I've tried different methods to retract the pintle with no success. Is the new VLV possibly defective is there another way to retract it that I'm not aware of? I've driven 2 more-xs no change except DTC P0507 comes up again. What's the cure, doc? Thanks Wrencherhead