Hey everyone, sorry its not a datsun but thought might ask here anyway

I just bought a 1984 nissan gazelle automatic
the car's fuel pump died and replaced that, but didnt work cos something's wrong with the relay so I took it to the mechanic for their electrician to fix it. The car was running fine when i test drove it and took it back home.
Next day the car starts but wont stay running on. now the mechanics doesnt wanna do anything about it but anyway

I visually checked the (2) temp sensors connections and cleaned the connectors.

Can it be my AFM or its pure electrical problem?

new sparkplugs, plug leads, rotor, fuel pump, fuel pump sender

Anyone knows what might be causing the problem? or anyone here can help me for a carton of beers or something?