I drove the Vic yesterday evening around 6PM on a short errand. Came back home and parked it. The car sat parked until about 1 PM today. I released the stem in the shrade valve, and gas shot up into the air about a foot; so, it's holding pressure at least overnight. Then, the car started immediately and ran fine. I might just get a low priced pressure test guage and keep checking it myself. As I stated earlier, the pressure was 50 psi with the switch on, then 38 psi with the car idling, per a guage a mechanic used to test it.

 

So I've re-read your thread, and your symptoms sound a lot like behavior I've observed in the past, on this 2002 Grand Marquis I'm working on. Specifically, many times when it gets started from cold, or after sitting several hours, it won't crank right up. It will either not start, or it will seem to start and then stall. But only on the first crank. Most times, you would crank it up and it would sputter for the first couple of revolutions after you release the key, then it'd rev up to a more normal 700 rpm.

Initially I thought it might be the ignition switch, and with good reason. When I pulled the switch, I stuck alligator clips on the terminals and metered the resistance. It was dropping between 50 and 250 ohms in some cases! Definitely enough to cause the fuel pump to run weakly, or to die. The practical effects of this were ~11.5 volts of ignition voltage with the key on, rather than a more normal 12.1 or more. And of course it had plenty of ignition voltage when the alternator was running. I've replaced the switch just out of good measure, since it was only like 30 bucks. I figured it would probably help those weak starts in the long-run.

But after having my fuel pressure gauge hooked up to it and seeing only 15 to 18 pounds of pressure at prime, I'm not convinced the problem was entirely the voltage drop across the ignition switch. I'm thinking it probably has an original fuel filter that needs replacing, and if that doesn't do it, then I may have a weak fuel pump. Now that you've replaced the fuel filter, I think the most logical thing for you to do is get a fuel pressure gauge and hook it up every time you go to start it after it's been sitting for more than a couple of hours. Even if you only did this every other time you start it, I think eventually you'll experience the problem while watching the gauge, and it'll give you a good idea whether your problem is fuel pressure-related, or something else.

 

another thing that could cause one to start hard or not start at all is the octane may not be high enough to allow smooth starting. but while reading all the info. given on this it still leads me to believe that the pressure isn't holding when the car sits for more than a couple of days. it shouldn't matter what the outside temp. is either. even though when an engine isn't running for a week it seems to be a little harder to start than normal. you can deal with turning the key on a couple of times before starting the car so that the pump builds the pressure up enough to start it,and, it gives you a little more time to get the money up enough to replace the pump because over time they have this tendency to weaken and not go out all at once

 

Thanks to everyone for your info. I bought a pressure gauge from Harbor Frght, and here's the results:
Ignition on, engine off-35 PSI
Idle-33 PSI
Quick punch of throttle-40 PSI
Vac line off regulator-42PSI
45 minutes after shut off-32 PSI
These look to be within specs, although kind of on the low end.

 

Compared to your 33psi at idle, 32 after 45 minutes is excellent. My truck with the suspected regulator problem, doesn't hold up near as good.

On this 2002 Grand Marquis, I took her for a spin for the first time since September.. hard to believe it's been that long. But before cranking it for the first time, I connected up my fuel pressure gauge and turned the key to run. It didn't budge from zero. I shook my head in disbelief, turned the key off, and turned it on again. It didn't budge again. I got sidetracked for a few minutes, but when I came back to it and turned the key to run, the needle barely moved.. probably 2 PSI or less. Turned the key off and back on, and again, barely registering anything. I cranked it and it did fire up, but very slowly in the manner I previously described. It registered 30 PSI at idle. But very telling was when I shut off the key, the pressure immediately dropped back to zero, in a matter of a few seconds. So now I'm thinking I have a regulator stuck in the open position, such that the fuel priming (by turning on the key) is of no effect.

To all you Ford experts, should I replace the regulator, or is there even a remote possibility that the fuel pump itself could have something wrong internally, causing a failure to properly prime, and an immediate leak-down too?

 

Gee, nobody ever called me an expert before, although they did call me a lot of other things.
Can you try this, clamp off the return line from the pressure regulator and if the pressure still drops ,could be a defective check valve in the pump module. If it stays up there then you know the pressure reg is faulty.What do you think?

 

Sounds completely reasonable to me. I hooked up my gauge and clamped off the return line in three places. The first two were from a wood-working clamp that exerts enough pressure to cause pain when clamped to the end of my finger, the third was from a pair of vice-grip pliers, tightened down as much as I could without fear of damaging the hose. I feel confident the clamping should have produced enough back-pressure to be noticeable, but it didn't - no change in behavior. So I'm thinking it's probably the check-valve on the fuel pump, like you said.

Or could it possibly be related to a vapor leak? I'm thinking no, because the whole check-valve apparatus should be sealed, and not subject to issues with vapor leaks from the tank. This vehicle has a known "evap small leak" which sometimes results in the smell of gas inside the cabin, while it's under operation, and often-times after fueling up too. I haven't gotten deep into it, and what testing I have done, was up in the engine compartment but not aft. I've always assumed the problem is somewhere between the tank, the evap canister, and the vapor line going forward to the evap purge device mounted on the firewall. Is it possible a vapor leak would cause leak-down in the fuel pressure?

Thanks in advance!

 

NO ! I don't think so.