Interment failure to start

Hi and thanks for using 2CarPros.

Since it sometimes requires starting fluid, my first suspect is the coolant temperature sensor. This sensor tells the computer the temperature and based on that information, the computer adjusts the air/fuel mixture. If it receives the wrong information, it may make the mixture too rich or lean. The result would be hard start, rough idle.

Now, the easiest way to make sure it is working correctly is with a live data scanner. Basically, the scanner will indicate what the computer is receiving and it should be near the ambient temp or engine coolant temperature.

If you find the sensor is bad, it is located on the left front of the intake manifold. See the attached picture for location.

If that is not the issue, then I recommend checking the fuel pressure. It may have fuel pressure drop off, the new pump may be weak, or the regulator may be bad. Check this link for testing both the pump and regulator.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Keep in mind, if the spark plugs are worn, they may not be able to burn a rich mixture. Starting fluid burns much easier.

Let me know if any of this helps.

Joe