And your lead turned out to be miraculous --- this morning I went to my car to diagnose it for MIL flashing as per your question. Prior to turning the ignition I just turned the key, on and off 3 to 4 times and there it was -- MIL flashing ---
But I noticed there was some malfunction in central locking and unlocking ---- Liana as you all know automatically unclocks the doors once your turn off the ignition switch -- History of this car is that it has after market remote central locking and unlocking mechanism also installed. Once ECM doesn't auto unlock the doors after the ignition switch is turned off for 3 times ,,, on the 4th instance MIL starts blinking
However as soon as I pressed the button on door panel to lock and unlock the door a signal from ECM was received and the MIL flashing was gone -- so it came out to be the OEM central locking conflict with after market module --- Now coming to the point what all have been told by the mechanics and 3S:-
a. Mechanics/Electrician --
(1) CKP sensor has gone bad and you need to change it ( yes a mechanic remembered all the names wiithout knowing what all they do)
(2) Your head needs surfacing to avoid engine malfunction
(3) Sell this crap, even if you lose few thousands
(4) After market CNG is the cause of the issue -- you need to check/replace all your emission control sensors
b. 3s
(1) problem seems to be because of after market CNG and we don;t deal such cars we can't even scan with the scanning tool --- go to a road side mechanic(Despite my insisting that at least check the DTC and inform me of the code , their answer was that you will simply spend money , good for nothing)
(2) your ECM is recording some misfire may be on CNG
What i have been through >>>
a. Cleaned the EGR as I thought it to be stuck
b. Planned to trace the Catalytic converter and remove it if that could be the cause
c. Checked my coils if they were short or unserviceable(thank god they were good)
d. Changed spark plugs (they were really in bad shape)
e. Removed all sensors grips and removed the dirt and slime form them
f. Had a doubt regarding transponder of Immobilizer viz-a-viz the key.
And in the end it just turned out to be
CENTRAL LOCKING ( AAAAARGHHHHHHH)