Thanks everyone for the feedback. I really appreciate. I have spent a lot of time with mechanic toyota and a generic mechanic as well. Got the emulator changed, got the fuel pump changed as well. We did check the connections of the wiring. Got the spark plugs checked as well. Also got the injectors checked again. One thing left that I did not check the "New Genuine Toyota fuel pump with assembly" got the filter changed though (it was almost due) one thing I noticed, one of the wires of the fuel pump had the plastic cracked, the wire was intact though. My mechanic is now suggesting to changed the wiring set , and while doing that will get the connectors cleaned as well. The performance is absolutely perfect on the cng, petrol is a tiny bit better after getting the plugs changed / throttle cleaned / fuel filter changed but it is not much, the car is missing on low rps below 2k-3.5k and the car really sucks on petrol.
So now the thing are
1- I will get the wiring set changed anyway.
2-will get the connectors cleaned.
3-throttle body cleaning as well.
4-will get checked if the is some mixing going on or air blockage. (already got the cng pipe disconnected and checked, it seemed a bit better but u can say a 30% increase of performance)
If nothing works I may get a fuel pump (genuine) changed and get the injectors checked again and that can be only done at toyota.
Brothers, any suggestions or heads up advice. I will really appreciate.
@Hash - Thanks again and any suggestions?
@Toxic & @mikmech -- Thanks a lot, I will get the points checked (if already checked I will recheck them).. plz do provide your suggestions regarding the above feedback.
@omkhan, bro mine was doing a 110-120km / cyl (CNG) and 9-10KPL. twice or thrice a month I can be a heavy foot.