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Car has idling problem it goes up and down with the vehicle almost stalling. Replaced egr valve, dpfe sensor, Mass air flow sensor, plugs and wires and it is still doing the same thing

Any help/suggestions anyone has please let me know. Thanks Diane

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Idling bad is usually the Idle air control or ( IAC ).If everything else is fine. remove and clean out the carbon or replace it. An Auto parts store will tell you where it is on your car. God-Bless!

Posted on Apr 21, 2015

Testimonial: "God Bless you too and thank you for the information. I am going to try what you suggest and hopefully that will work. Again Thank you so much....Diane"


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Problem with my car's idling. It idles high then drops low almost stalling. we have replaced numerous parts but it is still running rough.

Could be ISC or idle speed control which is like an electric air valve for the intake air. Some people clean this with WD40 after removing from chamber. Another part that affects idle is the crankshaft position sensor and the O2 sensors.

The repair place should have scanned the car for trouble codes. It is possible to have more than just trouble coded problems. I have mixed opinions about replacing the wrong parts like they did. You should not have to pay full price for wrong guesses. But used parts can not be sold as new once installed.

Apr 21, 2015 | 2001 Mercury Cougar

1 Answer

04Explorer wont go past10mpg codes say Egrcircuit mal,egrvalve sensor,manifold absolute pressure, barometric pressure circuit highinput, intake air temp circuit mal & intake air tempcircuit high input

Thats alot of codes, and most likely your vehicle has multiple problems. an 04 explorer gets it baromnetric pressure signal via the MASS-AIR sensor near the air cleaner. If there is a problem with that sensor, the intake air, barometric pressure, engine load calculation and main fuel calculations will all be affected or disabled causing the vehicle to run poorly or possibly not at all. Id recommend testing it using fairly advanced equipment and procedures. an OBD2 capable scantool that has datastream and snapshot ability at the very least , coupled with a volumetric efficiency calculator will tell you how well the MAF is doing its job if it is working at all. a labscope or good multimeter can also be used but they are less exact.
Depending on the type of fault and the fuel trim results, the entire problem could be in the Mass Air sensor circuit or its air flow sealing.

The EGR code is a seperate system. worst case if the EGR valve is stuck wide open it could also be a contributing factor to poor idling and MAF sensor codes and r=terrible mileage, however the EGR uses a sensor called Delta Pressure Feedback-EGR. (DPFE for short). This sensor measures the flow of the EGR by checking the differences in 2 different hoses coming off the EGR feed pipe; If either hose has a problem, you get EGR codes, if the valve has a proiblem you get codes, or if the DPFE has a problem, yes, you get codes. the DPFE sensors fail OFTEN! But I would still always verfify function using a scantool with enhanced ford datastream and manual activation ability before recommending a part.

Apr 07, 2015 | Cars & Trucks

3 Answers

EGR flow in our 2000 Ford Expedition is insufficient. What does this mean?

Exhaust gas recirculation flow reduced. Could be caused by valve or gunk in the flow path. I'll paste a little bit about troubleshooting below. If you need specific instructions for repairing your system, please reply with your engine size/type.

The Exhaust Gas Recirculation (EGR) system is designed to reintroduce exhaust gas into the combustion chambers, thereby lowering combustion temperatures and reducing the formation of Oxides of Nitrogen (NO x ).
The amount of exhaust gas that is reintroduced into the combustion cycle is determined by several factors, such as: engine speed, engine vacuum, exhaust system backpressure, coolant temperature, throttle position. All EGR valves are vacuum operated. The EGR vacuum diagram for your particular vehicle is displayed on the Vehicle Emission Control Information (VECI) label.
The EGR system is Differential Pressure Feedback EGR (DPFE) system, controlled by the Powertrain Control Module (PCM) and composed of the following components: DPFE sensor (also referred to as the backpressure transducer), EGR Vacuum Regulator (EVR) solenoid, EGR valve, and assorted hoses.


DPFE Sensor

  1. Disconnect the pressure hoses at the DPFE sensor.
  2. Connect a hand vacuum pump to the downstream pickup marked REF on the sensor.
  3. Using a multimeter, backprobe the SIG RTN circuit at the DPFE connector.
  4. With the ignition ON , signal voltage should be 0.20-0.70 volts.
  5. Apply 8-9 in. Hg of vacuum to the sensor. Voltage should be greater than 4 volts.
  6. Quickly release the vacuum from the sensor. Voltage should drop to less than 1 volt in 3 seconds.
  7. If the sensor does not respond as specified, check the power and ground circuits.
  8. If power and ground circuits are functional, the sensor is faulty.

EGR Valve Control Solenoid
  1. Remove the EVR solenoid.
  2. Attempt to lightly blow air into the EVR solenoid.
    1. If air blows through the solenoid, replace the solenoid with a new one.
    2. If air does not pass freely through the solenoid, continue with the test.

  3. Apply battery voltage (approximately 12 volts) and a ground to the EVR solenoid electrical terminals. Attempt to lightly blow air, once again, through the solenoid.
    1. If air does not pass through the solenoid, replace the solenoid with a new one.
    2. If air does not flow through the solenoid, the solenoid is OK.

  4. If the solenoid is functional but the problem still exists, check the power and ground circuits.

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.
  1. 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.

Sep 27, 2010 | 2000 Ford Expedition

2 Answers

Engine starts and stalls

1 Inspect EGR Valve EGR Valve Sticking Open/Leaking. 2 Inspect Idle Air Control Valve IAC Valve Sticking or Faulty. 3 Inspect Mass Air Flow Sensor Damaged, Loose, or Faulty Mass Air Flow Sensor or Circuit.

Jul 06, 2009 | 1987 Dodge Ramcharger

1 Answer

I have a 2001 mustang with a 3.8l I have a trouble code P0104

It is the DPFE sensor with out this your rpms will continue surge. Alot of people make the mistake of just replacing the EGR valve instead of the DPFE sensor which measures exhaust prssure going through the EGR vavle.

May 07, 2009 | 2001 Ford Mustang

2 Answers

Rough idle, surges when cold

have it scanned,ck' tps sensor,mass air sensor,idle air sensor for output...kev-mn.

Dec 10, 2008 | 2002 Ford Escape

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