Stalling during acceleration after a complete stop

2000 LINCOLN NAVIGATOR
130,000 MILES • 5.4L • V8 • 2WD • AUTOMATIC
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BUSINESSFRED
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Drives great and never had any issues.
But recently began stalling when I stop and then get going at a stop sign or right turn.

Sometimes it will almost stall but the engine will surge before over accelerating to compensate .

So far I have cleaned throttle body; IACV, MAF and ran some fuel injector cleaners.

I have also checked the elbows on the PCV hoses near the grommets.

It always starts right back up once I put it in neutral . Any ideas on what I should check next?

Also, I have no dtc codes.
May 14, 2018 at 11:32 PM
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ASEMASTER6371
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Good afternoon.

The IAC valve is the common issue and it cannot be cleaned. The area that is carbon-ed up is not accessible to clean. That must be replaced if deemed bad.

After you replace the valve, disconnect the wires to it and let the engine run. It should idle at 500 RPM. once you have adjusted the idle to that spec, then hook up the IAC and the speed should increase.

Roy
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May 15, 2018 at 8:55 AM
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BUSINESSFRED
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Oh, okay, I did not know that. I was wondering why it looked so clean.

Is there a recommended way to test the IACV ?
May 15, 2018 at 11:09 AM
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ASEMASTER6371
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With the engine idling, remove the connector from the valve and see if it stalls.

Roy
May 15, 2018 at 11:16 AM
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BUSINESSFRED
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Okay, it did not stall. Does this mean the issue is elsewhere?

It settled at 500 rpm just like you said.
May 15, 2018 at 11:19 AM
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ASEMASTER6371
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Yes it does. Let me check some things.

Roy
May 15, 2018 at 11:55 AM
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BUSINESSFRED
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Could it possibly be a failing fuel pump relay?
May 15, 2018 at 1:14 PM
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ASEMASTER6371
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Okay, no not the fuel ump relay.

The more I see this, it all comes back to the throttle body itself.

The only other thing I found was the EGR valve. If it does not close fast enough coming to idle, it can cause stalling.

Do you have a scan tool to monitor the EGR system?



Roy

May 15, 2018 at 1:29 PM
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BUSINESSFRED
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I do not have a scanner with live data.

Is the EGR valve the one with the single hose port against the firewall?

Or the one with two hose ports directly on the intake?

Can I clean this valve or is this a replacement only part?
May 15, 2018 at 1:50 PM
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ASEMASTER6371
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Single hose. Try removing the hose and driving it and see if it is any better.

No, it cannot be cleaned.

Roy

Removal:
1. Remove the upper intake manifold. For additional information, refer to Engine.



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2. Disconnect the Exhaust Gas Recirculation (EGR) valve vacuum line.



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3. Remove the bolts from the EGR adapter.



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4. Disconnect the two hoses from the EGR tube.
5. Raise and support the vehicle. For additional information, refer to Maintenance/Service and Repair.



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6. Disconnect the EGR tube lower fitting.
7. Lower the vehicle.
8. Remove the EGR valve and tube as an assembly.

Installation:
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May 15, 2018 at 1:56 PM
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BUSINESSFRED
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Is this for the 32 valve intech v8 4v ?
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May 15, 2018 at 2:18 PM
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ASEMASTER6371
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That is correct. It is the only engine listed.

Roy
May 15, 2018 at 2:27 PM
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BUSINESSFRED
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Okay, thank you Roy.
I hope this resolves my problem it is very concerning when it stalls on me.
May 15, 2018 at 2:45 PM
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ASEMASTER6371
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I agree. Keep us updated.

Roy
May 15, 2018 at 2:48 PM
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BUSINESSFRED
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I am not too familiar with this engine Internally. It is actually my first v8, but does this one also contain accessible EGR ports on the top part of the intake?
May 17, 2018 at 2:28 PM
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ASEMASTER6371
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At the EGR valve, yes.

Roy
May 17, 2018 at 3:02 PM