Head-Scratcher: Why won't my 06 coast when I leave of the gas pedal?

[altimaWarrior]

I have an 06 2.5S that runs like a champ - except that when I ease off of the gas pedal, the transmission does not unlock the torque converter clutch and let the car coast. Gas mileage is down. Sounds like it may be a stuck valve in the transmission, but could it be that I need a new accelarator pedal position sensor or to "relearn" the accelerator pedal release position? I tried the relearn procedure and it does not seem to effect this condition. Seems like the car thinks that I'm still pressing down the pedal! What about a cam shaft sensor or throttle body position sensor? Not sure if they play into the decision to unlock the TCC. Old school would point to a vacuum issue. I drained/replaced some of the ATF in an effort to possible free up a "stuck" valve - nothing yet (fluid seems fine).

Please help, I'm stuck (no codes) and the stealership is looking to "try" some sensors rather that logically troubleshoot. Can't afford to "try"!!!!

[TECHLINE08]

any codes stored in the TCM? Possible solenoid problem.