96 blazer advise

ok heres the senario, if you guys had a 96 blazer and replaced the fuel pump, filter and a complete tune up ,wire,plugs, cap and all. and the blazer wouldnt start unless you kept a stock oil heater plugged in what sensor would you start to replace first?

lil note here, i have also tried to spray ether in the throttle body when it is acting up and wont start and the ether has no effect at all. also no codes stored.

i am to the point where i have to believe it is a temp sensor issue because it starts absolutly perfect when i keep the oil heater pluigged in.

Starts ok, but will not stay running. You might want to change out the fuel pump oil pressure switch (Top rear of engine near distributor), if your oil pressure is OK and fuel pump pressure OK (60 - 65 psi).
In the start mode, the fuel pump relay is closed, powering the fuel pump. After the engine starts, the oil pressure switch is closed keeping the fuel pump running. If the engine stops, no oil pressure, fuel pump stops (Safety). This Can be do to too low oil pressure at sensor, bad pressure switch or electronic control circuit stopping the engine (need a scan tool to check processor / other sensors).