1995 Ford Windstar Fuel pressure within spec range

One thing to realize with fuel pumps and hydraulic sustems (any fluid) in general is that a pump creates flow. It is the restriction(s) in the plumbing which create pressure. So to answer your first question, if the fuel SYSTEM is not meeting PSI specs called for by the OEM, the pump may not be the problem.

Pumps go bad for two main reasons: Mechanically being worn out, or having "dead" areas where the motor brushes meet the poles. Usually, the latter happens more frequently and can be verified by hooking up the motor to a lab scope and viewing the amperage fluctuation as each brush passes over its corresponding pole. If one of the poles has a short or open circuit, the amperage will jump high or low for that instant the brush is in contact with that pole.

In an automobile, the pump creates fuel flow; it is (for the most part) the pressure regulator which creates and maintains the correct pressure. If you want to test the pump exclusively to see how much pressure it can develop, you would have to insert a fuel pressure gauge directly to the fuel line. Disconnect the fuel filter at the "in" port and hook up a fuel pressure gauge to the hose coming from the fuel tank. Or if you don't have the adapters, hook up your gauge to the "out" side of the fuel filter. Cycle the pump on for a few seconds and see what value you get. If your value is well above 45 PSI, you can figure the pump is in good mechanical condition. If there is an electrical problem with the brushes vs poles as decribed above, a lab scope will verify this.

Therefore, if your fuel pressure is low at the schrader valve with everything connected and the engine off, chances are the fuel pressure regulator is faulty. Hook up a vacuum pump to the regulator. No vacuum applied to the port simulates a high load, therefore should have higher pressure. Apply a vacuum to the regulator vacuum port and the fuel pressure should drop a few PSI.

Your 27 PSI, engine on, is low; likely due to a faulty fuel pressure regulator.

But before you run out and purchase a pressure regulator, just make sure the vacuum line attached to the regulator pulls a lot of air while the engine is running at idle. Pull the vacuum hose off while the engine is running; you should hear a strong hiss sound as air is rushing into the disconnected hose.

Your poor fuel economy may be due to this low pressure. If you have access to a OBD-II scanner which shows LongTermFuelTrim (LTFT) values, and if they are in the +15% range or more, the PCM is trying to compensate for the low pressure by increasing the injector pulse duration to maintain a proper air fuel mixture. However, there is still an imbalance in the fuel system, so haviing low fuel pressure and longer pulse duration is simply an effort on part of the PCM to keep the engine running at the correct air/fuel mixture. Your mileage will suffer as a result.
Furthermore regarding the bad fuel mileage, do you have an rotton-egg smell, or lots of soot at the tailpipe?

Automobiles rely on all systems being in balance with one another in order to run efficiently. I recommend getting the fuel pressure back to spec, then monitoring your LTFT, and recording your MPG to see if any progress is made.

Apologies for the delay in response.
After all your trouble, I'd suggest hooking up a different fuel pressure gauge to verify the one you have is providing accurate readings.

In a last ditch effort, since you mentioned a long time ago you had the PCM replaced, make sure it is flashed with the most recent Motorcraft/Ford software. Most likely, only your local dealer will be able to perform this service, unless you have a shop in the area which can specialize in this field.

Have you hooked up a good scanner and read the LTFT values (long term fuel trim)?

If I read your entry correctly, you saw fuel spitting out from the exhaust where the manifold meets the downpipe to the cat. Hmph. I'm not doubting you, but I am trying to envision this.

I'll answer your 3 questions to the best of my ability in the order you presented them.

1.) If you have an exhaust leak of the magnitude to have raw fuel spitting out, you'd definitely hear the exhaust rumble from that area. Otherwise, if the exhaust is quiet, the exhaust gasket is intact, and fuel could not be coming out.

2.) A stuck open injector: (And I am presuming the bank of cylinders you are talking about are nearest the radiator which makes the job easier). Try the following to confirm a stuck open injector. Remove the three spark plugs (cyl #'s 4-5-6). DISABLE THE IGNITION COIL PACK, and have an assistant crank the engine while you monitor the amount of fuel vapor emitted from the spark plug holes. If you have a stuck open injector, it will be constantly spraying fuel into the combustion chamber, and the piston will force the vapor out during its travel to TDC on the compression stroke. One of the spark plug holes will be emitting fuel vapor at a notable greater amount than the other two cylinders.

3.) You can go to any online car parts site such as partsamerica. Com or rockauto. Com or autozone. Com to compare part numbers per vehicle application. According to partsamerica, the part number for '95 Windstar fuel injector (Mfg. = BWD) is 49207. Compare that to the '98 Windstar fuel injector (Mfg. = BWD) is 57816. So I would say the answer is no. I suppose they have different physical or electrical characteristics.

Therefore, I present my commentary based on the conditions at hand:

Your poor fuel economy may be contributed to a bad fuel injector which was intermittently acting up during the past few months. It's just now that the fuel inj. Has called it quits and is failing completely. Good news for you because "ghosts" are difficult to track down and you can replace the part which has failed.
I doubt the single failed fuel inj was the main culprit to your low fuel pressure gauge readings. The low fuel pressure is still an open-ended question, but I feel the failed injector needs attention before trying to figure out the fuel pressure issue again. Fix first what you know for sure is wrong. Then the other stuff will iron itself out.
If you definitely do have a failed fuel injector, be sure to check your engine oil and/or change it. Fuel likely drained past the piston wall into the crank case and mixed in with the oil. Bad Bad. Change the oil immediately.

Check your catalytic converter(s) to make sure they are not burned out due to possible excessive fuel being dumped into the exhaust stream. Easiest way to do this is to hook up a scanner and monitor the O2 sensors voltage output.

When you get all your repairs done, I strongly suggest you have the vehicle hooked up to a scanner and monitor vitals such as Long Term Fuel Trim and the O2 sensors. Getting this data is very valuable to confirming the integrity of your repairs.

Finally, I can imagine all this is quite frustrating. Don't feel bad. We've all had engine symptoms which need lots of tinkering before we get it all right. I've surely had my share of experiences.