Tip & How-To about 1998-2003 Ford F150 4.2 4.6 5.4 Standard Cab and Super Cab AND 2001-

Ford F150 4.2 liter misfiring troubleshooting

Check all your gaskets good for leaks. Vacuum hoses for leaks. EGR valve and censer. clean intake tubes and injectors. clean MAF censer. also the injector and plug wires on the passenger side the T shape wiring harness is weak..DTC codes PO316 CYLINDERMISFIRE, PO300 MISFIRE STARTING, PO171 FUEL TOO LEAN, PO174COILPACK SHORTING.

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1998-2003 Ford F150 4.2 4.6 5.4 Standard Cab and Super Cab AND 2001- Logo

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1997 mercury cougar xr7, egr valve exhaust tube became loose followed by air leakage and lost of engine power, I tightened the exhaust tube but the loss of engine power still remains.. I tap on the gas, it sounds like is gasping for air and it stalls


Have to replace egr gaskets that burn away or tubes that rust out

What you have is exhaust system leaks & a lack of fuel control or
fuel trim, where the oxygen sensors are saying one thing and the cars computer doesn't know about the unmetered air getting in after
the maf sensor,thus the poor perfromance

You can not have ANY vacuum leaks-- evap system,intake,exhaust,
you get the idea

Try removing & capping the vacuum hoses to egr
The egr valve may be bad

Replace any oxygen sensors over 100,000,miles
Replace spark plugs in motor over 3 years
Clean Maf Sensor (crc maf cleaner)

Jul 16, 2014 | Cars & Trucks

1 Answer

what is a egr valve


  1. Install a tachometer on the engine, following the manufacturer's instructions.
  2. Detach the engine wiring harness connector from the Idle Air Control (IAC) solenoid.
  3. Disconnect and plug the vacuum supply hose from the EGR valve.
  4. Start the engine, then apply the parking brake, block the rear wheels and position the transmission in Neutral.
  5. Observe and note the idle speed.
If the engine will not idle with the IAC solenoid disconnected, provide an air bypass to the engine by slightly opening the throttle plate or by creating an intake vacuum leak. Do not allow the idle speed to exceed typical idle rpm.
Using a hand-held vacuum pump, slowly apply 5-10 in. Hg (17-34 kPa) of vacuum to the EGR valve nipple.
  1. If the idle speed drops more than 100 rpm with the vacuum applied and returns to normal after the vacuum is removed, the EGR valve is OK.
  2. If the idle speed does not drop more than 100 rpm with the vacuum applied and return to normal after the vacuum is removed, inspect the EGR valve for a blockage; clean it if a blockage is found. Replace the EGR valve if no blockage is found, or if cleaning the valve does not remedy the malfunction.


EGR Valve Removal & Install
3.0L OHV (2 valve) and 3.4L SHO engines

b9175c5.jpg

Fig. : EGR mounting-3.0L OHV (2 valve) engine

5fcd84e.jpg

Fig. : EGR mounting-3.4L (SHO) engine

4552fc2.jpg

Fig. : Remove the two retaining bolts and...

b849310.jpg

Fig.: ... remove the valve from the intake manifold

795549d.jpg

Fig.: Thoroughly clean the mating surfaces of the manifold and the EGR valve (if being reused)
  1. Disconnect the negative battery cable.
  2. Remove the vacuum hose from the EGR valve.
  3. Using a 22mm wrench or crowfoot, disconnect the EGR valve-to-exhaust manifold tube from the EGR valve.
  4. Remove the EGR valve mounting fasteners, then separate the valve from the intake manifold.
  5. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
To install:
  1. Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts to 15-22 ft. lbs. (20-30 Nm).
  2. Connect the EGR valve-to-exhaust manifold tube to the valve, then tighten the tube nut to 26-47 ft. lbs. (35-65 Nm).
  3. Connect the vacuum hose to the EGR valve.
  4. Connect the negative battery cable.

3.0L OHC (4 valve)

d8a563e.jpg

Fig. : EGR mounting-3.0L OHC (4 valve) engine
  1. Disconnect the negative battery cable.
  2. Remove the vacuum hose from the EGR valve.
  3. Remove the two EGR tube-to-EGR valve retaining nuts.
  4. Remove the EGR valve mounting fasteners, then separate the valve from the intake manifold.
  5. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
To install:
  1. Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts to 15-22 ft. lbs. (20-30 Nm).
  2. Connect the EGR valve-to-EGR tube, then tighten the retaining nuts.
  3. Connect the vacuum hose to the EGR valve.
  4. Connect the negative battery cable.

Tell us news.

Oct 12, 2012 | 1998 Nissan Maxima

1 Answer

What is code P0171?


P0171

A lean fuel condition can be caused by:

* Low fuel pressure due to a weak pump or leaky fuel pressure regulator. (use a fuel pressure gauge to check fuel pressure at idle)

* Dirty fuel injectors. (try cleaning the injectors)

* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body. (Use a vacuum gauge to check for low intake vacuum)

* Leaky EGR valve. (Check operation of EGR valve)

* Leaky PCV Valve or hose. (Check valve and hose connections)

* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires

Jul 14, 2010 | 2002 Kia Sportage

3 Answers

EGR Valve not working


EGR Valve Testing
  1. Install a tachometer on the engine, following the manufacturer's instructions.
  2. Detach the engine wiring harness connector from the Idle Air Control (IAC) solenoid.
  3. Disconnect and plug the vacuum supply hose from the EGR valve.
  4. Start the engine, then apply the parking brake, block the rear wheels and position the transmission in Neutral.
  5. Observe and note the idle speed.
If the engine will not idle with the IAC solenoid disconnected, provide an air bypass to the engine by slightly opening the throttle plate or by creating an intake vacuum leak. Do not allow the idle speed to exceed typical idle rpm.
Using a hand-held vacuum pump, slowly apply 5-10 in. Hg (17-34 kPa) of vacuum to the EGR valve nipple.
  1. If the idle speed drops more than 100 rpm with the vacuum applied and returns to normal after the vacuum is removed, the EGR valve is OK.
  2. If the idle speed does not drop more than 100 rpm with the vacuum applied and return to normal after the vacuum is removed, inspect the EGR valve for a blockage; clean it if a blockage is found. Replace the EGR valve if no blockage is found, or if cleaning the valve does not remedy the malfunction.


EGR Valve Removal & Install
3.0L OHV (2 valve) and 3.4L SHO engines

b9175c5.jpg

Fig. : EGR mounting-3.0L OHV (2 valve) engine

5fcd84e.jpg

Fig. : EGR mounting-3.4L (SHO) engine

4552fc2.jpg

Fig. : Remove the two retaining bolts and...

b849310.jpg

Fig.: ... remove the valve from the intake manifold

795549d.jpg

Fig.: Thoroughly clean the mating surfaces of the manifold and the EGR valve (if being reused)
  1. Disconnect the negative battery cable.
  2. Remove the vacuum hose from the EGR valve.
  3. Using a 22mm wrench or crowfoot, disconnect the EGR valve-to-exhaust manifold tube from the EGR valve.
  4. Remove the EGR valve mounting fasteners, then separate the valve from the intake manifold.
  5. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
To install:
  1. Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts to 15-22 ft. lbs. (20-30 Nm).
  2. Connect the EGR valve-to-exhaust manifold tube to the valve, then tighten the tube nut to 26-47 ft. lbs. (35-65 Nm).
  3. Connect the vacuum hose to the EGR valve.
  4. Connect the negative battery cable.

3.0L OHC (4 valve)

d8a563e.jpg

Fig. : EGR mounting-3.0L OHC (4 valve) engine
  1. Disconnect the negative battery cable.
  2. Remove the vacuum hose from the EGR valve.
  3. Remove the two EGR tube-to-EGR valve retaining nuts.
  4. Remove the EGR valve mounting fasteners, then separate the valve from the intake manifold.
  5. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
To install:
  1. Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts to 15-22 ft. lbs. (20-30 Nm).
  2. Connect the EGR valve-to-EGR tube, then tighten the retaining nuts.
  3. Connect the vacuum hose to the EGR valve.
  4. Connect the negative battery cable.

Tell us news.

May 04, 2010 | 1999 Mercury Sable

3 Answers

1999 FORD EXPEDITION 2WD 4.6L EGR VALVE,EGR CONTROL &EGR POSITION SENSOR REPLACED NO FIX STILL BAD FOW CLEANED HOSES


Remove the throttle body housing on the top of the intake, it is a 90 degree tunnel like small piece held by 4 small bolts, turn it over and look for two holes, these holes are for the EGR valve flow, they are probably plugged up with carboned crud, clean them out with the tip of a screwdriver if neccessary to remove all the crud, once its clean reinstall it and reset your check engine light, hope this helps, let me know

Dec 04, 2009 | 2000 Ford Expedition

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