What's acceptable once you turn the car off?

When I first turn it off, it seems to drop to about 35, then slowly rise to 40 over about 15 seconds, and hold there for at least a 1/2 hour.

However, after about 1.5 hours after shutdown, it bled down to around 32 psi...

I also checked it about 12-16 hours (the next day) after shutdown, and it was at 0.

So, what is acceptable? How long should it hold pressure? And if this isn't acceptable, would it be my injectors or regulator leaking?

My fuel pressure at idle is about 36.5, and at WOT it is about 43.5, which seems to be normal. So, I'm thinking that the FP regulator is ok...

I'm trying to hunt down a low MPG I've been getting for awhile, and a bad stumble under low RPM load when started first thing in the morning (lasts about 5-10 mins).

Thanks!

 

Your fuel pressure sounds normal.