2000 G20 won't stop stalling

[vega_box]

2000 Infiniti G20
production date 02/00
Automatic
ECU mec12-071 LN

OK so my wife is pregnant so this is a big issue.
first it would only happen during the evening after the veh. has been driven and is hot.
Car would stall while she is driving and coming to a stop.
Sometimes not restarting right away.
code for the veh. was P1336 for the crank position sensor and P0505
I have been told that a lot of times the MAF sensors go bad on the G20

I cleaned the throttle body IACV and replaced the Crank Position sensor and then had it relearned at the dealer...
No fix

Replace the Maf sensor...
No fix

Recenetly is just started stalling and cutting off whenever she drives the car. Freeway or street.
Took it to nissan and had the CPS replaced again along with some wires they said looked tampered.
Still no fix. They followed the wires back to the ECU and said it could possibly be an ECU issue.

Even after all these repairs and parts I'm still getting the same codes
The car won't go past 40mps after is stalls on her the first time. MPG has gone down. Loss in power especially going up hills along with the stalling and crank but no start issue. Sometimes it won't even crank at all. No misfire

I'm looking at purchasing a used ECU now and praying for the best. I'm I leaning the right way for a fix that no one can locate??

I have also been told that it sound like my catalytic converter is blocked up. Could this cause an issue?

TIA

[RED_DET]

Check the wires underneath the battery for any corrosion or loose connections. One of those wires run to the main ecu relay and a friend of mine had this issue come up on his nissan sentra.