I did observed that the trigger bar was not going high as it can go and not catching something, but not sure if it's the disco or the bottom part of the sear leg.
Response to the replies above:
1. pre -travel screw is not too far out, one of the first thing I checked.
2. yes there is a pre=travel screw on Stock 3's
3. I did re-installed the original plunger with the original spring but did not help. Crossed this off the list to check.
4. will check again for any burrs and I only polished the disco with Flitz , not too much.
Beer Baron and Eng. Eli;
With your replies and suggestions, I am now armed with better info and understanding of how a Tanfoglio trigger action works and hopefully can solve this issue. Thank you so much for your help.... I will post an update as soon as I get the chance to work on the gun again.