Problem solved. It was a piece of tape that I used around the crankcase ventilation tube elbow at the snorkel that came off and got sucked into the airstream. LUCKILY, it got caught at the throttle plate, OMG. It was preventing the butterfly from going to closed/idle position. Removed it, cleaned the throttle body and did a quasi-relearn process, and back to a normal running engine. That threw everything off !
Thank you very much for your help!! - the final guess was right at where the issue was, the TPS/throttle body.