stumped

Hi, I have a 1977 280z,I started having problems last year driving home,it stalled and bucked,since then I have replaced the engine from gearhead,thermotime sensor,cooling sensor,tps,distributor,rotor,plugs,ngk,afm,throttle body,battery,starter,alt,fuel inj.fuel pump,filters,vac hoses,fuel hoses,cleaned out fuel tank,installed pre filter before fuel pump,replaced fuel inj. relay,ign relay,The engine still stalls when you connect the cooling sensor,idles great when the cooling sensor is not hooked up but stalls under load.Completely lost on this one.