Question about Ford Cars & Trucks

1 Answer

What is the fuel line pressure suppose to be,while running,on a 1998-4.6l-F150-V8?......Im at 30-31 psi....Having Misfires

Having #1 and #2 misfires.Having Lackof upstream heatedO2 sensor switch. Sensor indicates Lean-Bank #1

Posted by on


1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Top Expert:

    An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.


    An expert that got 20 achievements.


    An expert that got 10 achievements.

  • Ford Master
  • 21,873 Answers

Normal fuel pressure at idle is 30-40 psi. You should be able to disconnect the vac line to the regulator and see pressure go up.
If you think pressure is low, the fuel filter would be the first suspect.
The pressure regulator could also be faulty.

Posted on Dec 09, 2012


6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

  • 1 Answer

SOURCE: location of O2 sensor in bank 2, 99 5.4 expedition, running lean

I have a ford 2003 windstar that was running very rough when cold and almost stalling. engine light came on. went to autozone and they read the codes for free and told me it was running lean on Bank 2 also. i came home searched for the O2 front sensors online using the info autozone gave me. there are 2 front sensors on my car that need to be replaced at the same time. look for ones that have a direct plug in and don't need wire splicing. the ones without the wiring harness are cheaper but more of a pain, i think.
they were fairly easy to replace. getting access with the wrench was the worst. reset the light by disconnecting the battery for a few minutes. seems fine now and the light hasn't come back on.

Posted on Jan 25, 2009

  • 41 Answers

SOURCE: trouble code 1131 lack of ho2s bank 1 sensor 1 switches sensor

if sensor indicates lean check the fuel trim if long term fuel trim is above +7 them test sensor with a piko lab scope or watch scan data and create a rich condtion by snping the throttle wide open and watch the sensor if it start to read around 700to 900mv its ok, then create a vacume leak and the sensor should read 100to 300mv i your sensor is in this range quickly its good with in 1to2 sec.

Posted on Mar 22, 2009

  • 5081 Answers

SOURCE: I have a P0171 to lean bank 1 error code

oxygen sensor, vacuum leak, and yes it could most definitly be if you swaped the wires of the firing order accidently you will get a code p0171 Check the tubing going from the air filter to the intake manifold to see if it has come loose. This might account for extra air going into the intake manifold than the computer is aware of. Otherwise it may be due to a faulty(or dirty) MAP/MAF sensor. Another possible cause is from low fuel pressure due to restricted fuel lines or a bad fuel pump.

Posted on Jul 28, 2009

  • 13 Answers

SOURCE: ford f150 2003 po171 always

Code Po171 indicates a lean condition on cylinder bank #1 of the engine. This is the drivers side of the engine. I would suggest replacing both front oxygen sensors as a pair to start. An oxygen sensor has a life span of about 5 years and yours are now 9 years old if they are original. When they get older they are slow to respond to changes in the oxygen content of the exhaust and can trigger a code Po171. If you continue to have the same code set after the replacement of both oxygen sensors then it is time to find out why your engine is running lean. Some of the most common causes are an ignition misfire and a vacuum leak. I have also seen Fords EGR flow sensor (known by Ford as Delta Pressure Feedback sensor) to cause problems like that as well. A good mechanic with a scan tool can usually spot a problem like that in a few minutes.

Posted on Mar 01, 2011

  • 547 Answers

SOURCE: check engine light code P0171

That code is a good O2 sensor reporting a lean condition. Lazy people and part stored just say it is the O2 sensor because they don't know how to fix it. Bank 1 is the side of the engine with the number one cylinder. That bank has a lean condition meaning it doesn't have enough fuel for the given amount of air. Since this is only affecting one side of the engine, that narrows down possible causes. Possible causes would a leaking intake gasket or a broken vacuum hose on that side. Since both sides get fuel from the same pump and rail, this wouldn't be a fuel pump or regulator issue. It can, however, be an indication of a bad fuel injector on that side of the engine. The MAP sensor also couldn't cause this code because, just like the fuel pump, that MAP sensor works for both sides of the engine and the code is only for one side. I would drive it for a couple more days to see if you get any additional codes that could help point you towards the actual problem. In the meantime, I would check for vacuum leaks (look at the rubber hoses and listen for high pitch hissing or sucking sounds.)

Posted on Mar 03, 2011

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

I have 1997 Cadillac Deville 4.6 v8 Northstar 32 valve it has 90 pounds fuel pressure an it should have 40 to 50 pounds why is the fuel pressure so high?

Fuel pressure regulator . plugged fuel return line .

With the ignition switch ON and the fuel pump running, the fuel pressure indicated by the fuel pressure gage should be 333-376 kPa (48-55 psi).
The Fuel Pressure Check determines if the fuel system is providing fuel pressure. The components involved include the fuel tank, sending unit, pump, pipes and hoses, pressure regulator, fuel rail, and injectors. Also checked is the electrical operation of the fuel pump relay. This chart requires J 34730-1A , Fuel Pressure Gauge J 37287 , Inlet and Return Fuel Line Shut-off Adapters.

Feb 18, 2017 | Cadillac DeVille Cars & Trucks

1 Answer

What are the pump pressures supposed to be at the fuel rail?

Hi Arlene, Im AL the owner of Big As Auto Repair.

Arlene, every vehicle is different, but if you have a pressure of around 50 PSI and when your turn the engine off it holds pressure around 50 PSI and doesn't drop to zero then your fuel pump is not the problem. NOTE: If you have a diesel the pump pressures will be different then above. Hope this helps and please visit my auto-repair-website and tell me what kind of issue you are having with your vehicle. Please visit:

Nov 29, 2015 | Cars & Trucks

2 Answers

I have a 2005 Ford Explorer, 4.6L V8. Im having random misfire. Power goes in and out. I changed all 8 coils and spark plugs. Does anyone know of any other reason im losing power?

random misfires are not always the electronics and plugs but include the injectors and low fuel pressure.
check fuel pressure and injectors

Aug 30, 2015 | Ford Cars & Trucks

1 Answer

How much fuel pressure dose the 95 quest supposed to have

check for a blocked filter first. The fuel pressure should be up to 60 psi and is normally set by the pressure sensor and fuel pressure regulator in the fuel manifold. Try removing the fuel cap and see if that improves the situation and if so run the fault codes as there is a problem venting the tank at the canister valves

Mar 01, 2014 | Nissan Quest Cars & Trucks

1 Answer

I have a 1999 ford f150.. With a 4.6 v8 it has 170k miles.. My problem is that when the truck warms up it tends to hesitate and backfire when I try to excelarate..

Check your fuel pressure it should be 30-45 psi.There is a test port on the fuel rail to connect a fuel pressure test gauge.

Jan 31, 2012 | 1999 Ford F150 Regular Cab

1 Answer

On my 1992 Ford F150,Seems that my fuel line is bleeding back at night. I have to prime the intake, then it runs fine. Is there a check valve somewhere that could have gone bad?

Check the fuel pressure regulator by pulling the vacuum hose off and look for fuel if any fuel drips out tor you see any raw fuel then the regulator is faulty.If the regulator checks out to be good then check your fuel pressure it should be 45-60 psi if its the 4.9 c.i. 6 cylinder motor and if its the 5.0 or the 5.8 V-8 motor then it should be 35-45 psi with the ignition on and engine off.

Nov 05, 2011 | 1992 Ford F150 SuperCab

1 Answer

Low fuel pressure 1996 savana 5.7 V8 central sfi

The only thing left in this system is the fuel pressure regulator. You need to check pressure before the regulator and after the regulator if there is the problem then you need to replace it. I hope this helps. Don't forget to rate my answer.

Feb 18, 2009 | 2001 GMC Savana

1 Answer

Ford 150 gas mileage issues

Your O2 sensors may be freaking out. The O2 sensors tell the ECM how much fuel to send through the injectors. When the O2 sensors quit working right, the ECM has no idea what to do with the fuel. Do a fuel pressure test as well. If the pressure regulator is working correctly, it'll go through alot of fuel as well. You should be at 40 psi. When running you should be at 37 psi.

Jun 30, 2008 | 1995 Ford F150 Styleside Regular Cab

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

111 people viewed this question

Ask a Question

Usually answered in minutes!

Top Ford Experts


Level 3 Expert

80407 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers


Level 3 Expert

5687 Answers

Are you a Ford Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides