So here’* my problem. When the car gets to operating temperature it will sometimes sputter and die. When it does it won’t start back up right away. Sometimes it runs fine all day. I have checked fuel in the rail, pump works and relay comes on. It only happens sometimes and I can’t recreate the issue that causes it. Any help?

We need to see if it'* spark or fuel.

How many miles on it?

What is the fuel pressure when warmed up at idle?

The car has almost 250K. So I ran a fuel pressure gage and at start up and warmed up it was 40ish psi. Haven’t tested spark but it wouldn’t even stumble today.

Start up

Warmed up

That pressure is low.

Yep, low pressure.

So low pressure is that a bad pump or fuel pressure regulator? It ran just fine for well over an hour yesterday.

Probably a bad fuel pump, but replace the regulator anyways on that engine. Too many go bad then burn the car to the ground.

So 2 questions then. Is the pump accessible through the backseat? And what should the pressure be normally?

You have to drop the tank.

48-55PSI