Why sould the fuel cut off after 10 to 20 seconds at idle

I don't think that's it. The air temp sensor checks out. About 5 amps to it and there is a good ground. I did a temp check and the ohms dropped as I increased the temp. Any other Ideas? When the engine stalls, the injectors stop immediately. No stumble. As if the electricity or the gas is suddenly cut off. It does it at dead idle and when I am feathering the throttle.

Sorry "5 volts to it" Long day.

When I turn the ignition on, the fuel pump runs for a few seconds and stops if I do not start the engine. What keeps the pump running when I do start the engine?

Battery and cables are new and they are grounded well to the new heads. No rust or corrosion. The alternator charges at about 13.8 at 2000 rpm with all accessories on. I did not check the amperage. I have done a lot of the usual systems checks but I do not know how the TBI system is supposed to function. I understand the fuel pump is supposed to run for a short time to put adequate pressure to the lines and TBI. I do not know how power is maintained to the fuel pump after the engine has started. Or how to troubleshoot the electrical that controls the fuel pump. If you are wondering. Checking the air temp sensor is like checking a thermostat. Hold it so the tip is in water. As the water warms the resistance should drop from about 1.2 at chill to about .3 at about 180 degrees. A temperature controlled rheostat.

I thank you for your help. I started getting my ASE certs when 50 years ago as a hobby. Have not done anything in the last 20+ years. Though I understand the theory, I lack the hands on experience with injection systems to do any practical troubleshooting. I found the air temp sensor testing on YouTube and was amused at it's simplicity to maintain the air/fuel mix. So far I have not been able to find a schematic to show which circuits control the fuel pump operation at what times. The fact I could keep it running by feathering the throttle when I had low fuel pressure has me baffled, unless there might be a problem with the new ECM or a loose wire that just wants to drive me nutz. Tomorrow I will continue to pick the brains of those of you that know more than I. I appreciate your input and hope you might be able to help me solve my issues.