So the diagnoses was the air flow sensor was not working properly, cleaned and installed again didn't have a chance to test fuel efficiency again as of yet.
Removed front bumper, grill and started some minor fixing / cable changing. Some of cables are in horrible condition with insulation breaking exposing wires.
I need to replace the metal support frame as its in very bad condition its preventing proper bolting of all the interior and exterior parts.
I had to do some make shift bolting to keep things from swaying around including AC air fan, ac radiator etc.
The problem is that all the fixes done on the car seems to have been out of spec, they just "winged it" rather than properly repair the issue. This has a led to a series of screws, bolts etc that has nothing to do with how the car was supposed to be bolted.
Even grounding rather than swap the cable, they just added additional ones.
After replacing the main engine ground cable, the car seemed to idle very low even at cold. I am not sure if that is from the previous cable or the new one.
Recently the car would idle at 1000 - 1200 when cold and runs at 700 - 800 when warm, it now starts at 600 and seems to struggle a little to keep running.
I am also surprised with the yellow earth cable which seems very small in comparison to the other side. I don't know how much negative cables or how many connections the car should have but i really need to do some reading on this. Whoever worked on this car should be flogged in a public square ......