My cousin recently got a 98 corolla with 4AFE swapped in. I checked, and there's no MAF connection (the wires supposed to be coming out of MAF are all cut and taped together). And couldn't find any O2 connected as well.
He told that electrician has issued this statement "The engine is EFI, but your wiring is not that of EFI" :).
It's just another example of juggaroo swap, with daysi wiring all over.
The engine is running fine on CNG (and running on petrol as well, maybe too rich though).