Fuel Pressure Specs?

Six cylinder front wheel drive automatic 161,000 miles.

My car has the 3.0L OHV engine. I have been experiencing a loss of power and "miss" at highway speeds since I have owned the vehicle. I own both the Ford shop manual and the Ford emission control and diagnostic manual. Both show different specs for my fuel pressure. The shop manual says 50-56 psi (350-380kpa). The emission diagnostic manual says 39-65 psi (270-450kpa), both koer. I have monitored the fuel pressure while driving with my scan tool and it stays near 270 kpa and fluctuates slightly over and below that number. Turning the A/C on is when the problem is most noticeable, and I do not see a rise in fuel pressure when I do. I am thinking I should check the fuel pump driver module as I have already replaced the pump with another unit (used). Also, what spec should I look at?

So what is the 50-56 psi specs for in the Ford shop manual? Alldata. Com lists both of these specs on their site for this car.

So then is it normal for fuel pressure to stay at the bottom of the spec (270 kpa), fluctuating slightly up and down, though out the entire time you are driving? The fuel pressure stays steady on flat interstate, on hills, accelerating with the A/C on and off. Thanks for all your help.

Thanks for all your help. I have one more question regarding this. I installed another fuel pump driver module and the fuel pressure went up to around 400 kpa at idle. I checked the pressure again with my scanner today at idle and got the same results. I checked the pressure with a manual gauge at the same time and got around 60 psi. I decided to drive the car and the more I drove the more the pressure dropped. I am baffled as I was sure the pressure would rise with load, as load increased while driving. I am just about at wits end on this. Thanks again.

As far as the fuel pressure is concerned, I am sure you're right. I am just baffled at what is causing the car lose power (like a gently buck at highway speeds) and miss. All ignition components were tested at a local dealer and passed. I am going to put the vacuum pump I just purchased to use on Tuesday and begin checking for leaks. Thanks again. I really appreciate your help.

The plugs, wires and coil have been replaced. The original coil had a crack and was causing a misfire. I am not seeing any information about misfires with my scan tool. It shows everything as okay. I am noticing that it records the results of the diagnostic tests it runs on the EVAP system as sometimes high or low. I am going to check for vacuum leaks and take the vehicle to a transmission shop to make sure it is not the torque converter.

This problem intially started after the car struck on dog on the front right corner. After the initial impact my wife pulled over and shut the car off. Afterwards, she tried to start the car and it would not start. 15 minutes later it started with no problems, but over the last two weeks this problem persisted, starting and then not starting. One day She had filled up with gas and it would not start for 30 minutes at a gas station. Another day it would not start and we had to wait til the next morning for it to start( the car had an 1/8th of tank of gas at the time). We took it to an parts store and had the OBD II codes checked, no problems there. But once again the car would not start. The battery checked good and at no time had the fuel inertia switch ever activate. My questions are the following,
Is it the fuel pump, starter, or fuel pressure? If it is the fuel pressure, how do I fix the fuel pressure?

The engine will turn over and run as any other day when I start it for the first time. No problems occur while driving either. After the vehicle is shut off and we try to restart it nothing happens apart from the electronics turnning on. It will not crank over nor do I hear the starter engage. No sounds whatsoever.

I have the same car, same problem. Dealer told me it's my starter, too many amps. I've very skeptical that this is a correct diagnosis.

2000 Ford Taurus wagon, **FLEX FUEL** V-6 engine running on regular E10. Began stalling intermittently. Would run rough for 30-60 seconds or so and then die, both while driving and while idling. Would restart just fine. Began happening more and more frequently and threw a Check Engine code (but I don't know what it was, repair shop says they “lost it”.) Then one morning it wouldn't start (mild Oregon climate 55F overnight). Had it towed to an independent repair shop. They read the code and measured fuel pressure at the fuel pressure test port (on the very far end of the fuel injection rail from the gas tank) at 3psi. They diagnosed a bad fuel pump and replaced. Told me it was ready to pick up. It had been sitting out overnight. When I picked it up, it wouldn't start. With lots of cranking it finally started but ran extremely rich. Strong smell of raw gas out the exhaust and clouds of fumes (not burned oil, just unburned, rich exhaust). Gave it back to the shop. They read code P0191 and diagnosed a bad fuel flow sensor (device right at the beginning of the fuel injection rail) and replaced, but it didn't affect the problem. It will still sometimes have trouble starting and run very rich when starting from cold (cold = 55F). Without touching the throttle, engine can be shut off and started again and it will be just fine. Shop doesn't know how to proceed. I walked through with them their diagnosis of the bad flow sensor. Upstream of the flow sensor is an oval-shaped metal enclosure with fuel lines going in and out, and an electrical connection. They didn't know what this device does (neither do I). I suspect it might be the electronic fuel pressure regulator.

It is unlikely that there would be two bad components at the same time in the fuel delivery system. I suspect that the bad fuel pump was a misdiagnosis, and the bad flow sensor is obviously a bad diagnosis. There are two TSBs that might be pertinent � TSB14187 & TSB14041. But I don't understand completely the flex fuel system. What controls the fuel pressure to the fuel injection rail? What device senses the ethanol concentration of the fuel system? What is that oval box in the fuel line? What does the engine change in response to the ethanol concentration? What could be the true problem here that would fix the car?

The automotive forum link was interesting � it shows that flex fuel issues can be very hard to troubleshoot. But nobody there was getting a P0191 code. That code was read by the repair shop; they didn’t mention any other codes along with it.

What is the description that goes with a P0191 code?

I know what basic elements need to be in the fuel supply system, but not what order they are in the Taurus. Do you guys have access to the vehicle manuals? Can you tell me how the components of the fuel system are laid out (what components, in what order, starting at the fuel pump and ending at the fuel injector)?