well guyz, got my issue resolved yesterday. To my surprise, it was merely a cracked worn out wire, just above the throttle body.
Took my car to an expert mechanic, told him the issue, he inspected it all over for about 15 mins and then pulled out this grip. Opened all the tapes, bla bla, cut a few wires, joined them again, threw the bad ones away, put some new ones in and whoalla.
the car is perfect. Idling, startup, even I feel it to have become more responsive now. No rpm drops, no sluggish movements, no nothing.
Since faizan bhai's problem wasn't until he got the TB cleaned, so I suspect the issue to be the same with him as well.
bro, do check the grips and wires just above of the throttle body.