Hi,
The pressure when the key is first turned on should be much higher than 20 psi. Interestingly, when you have it running, it jumps to the normal range. However, I noticed when you hit the throttle, the gauge didn't jump.
I suspect it is the fuel filter/regulator issue. This component is located at the top of the fuel tank and fuel module. See pics below. See number 1 in pic 1 and number 3 in pic 2.
That is my first suspect. It requires the removal of the fuel tank to be replaced. Starting with pic 3, I attached the directions for the replacement of the component. Take a look through them and let me know if you have questions or are comfortable performing them.
If this was my vehicle, I would likely remove and replace the fuel pump assembly at the same time. You wouldn't want to remove the tank again. It's just a thought.
Take care,
Joe
See pics below.
Images (Click to make bigger)
Monday, September 25th, 2023 AT 8:16 PM