Stalling during acceleration after a complete stop

Tiny
BUSINESSFRED
  • MEMBER
  • 2000 LINCOLN NAVIGATOR
  • 5.4L
  • V8
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
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.
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Monday, May 14th, 2018 AT 11:32 PM

15 Replies

Tiny
ROY B
  • EXPERT
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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Tuesday, May 15th, 2018 AT 8:55 AM
Tiny
BUSINESSFRED
  • MEMBER
Oh, okay, I did not know that. I was wondering why it looked so clean.

Is there a recommended way to test the IACV?
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Tuesday, May 15th, 2018 AT 11:09 AM
Tiny
ROY B
  • EXPERT
With the engine idling, remove the connector from the valve and see if it stalls.

Roy
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Tuesday, May 15th, 2018 AT 11:16 AM
Tiny
BUSINESSFRED
  • MEMBER
Okay, it did not stall. Does this mean the issue is elsewhere?

It settled at 500 rpm just like you said.
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Tuesday, May 15th, 2018 AT 11:19 AM
Tiny
ROY B
  • EXPERT
Yes it does. Let me check some things.

Roy
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Tuesday, May 15th, 2018 AT 11:55 AM
Tiny
BUSINESSFRED
  • MEMBER
Could it possibly be a failing fuel pump relay?
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Tuesday, May 15th, 2018 AT 1:14 PM
Tiny
ROY B
  • EXPERT
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
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Tuesday, May 15th, 2018 AT 1:29 PM
Tiny
BUSINESSFRED
  • MEMBER
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?
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Tuesday, May 15th, 2018 AT 1:50 PM
Tiny
ROY B
  • EXPERT
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.

ImageZoom/Print

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

ImageZoom/Print

3. Remove the bolts from the EGR adapter.

ImageZoom/Print

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

ImageZoom/Print

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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Tuesday, May 15th, 2018 AT 1:56 PM
Tiny
BUSINESSFRED
  • MEMBER
Is this for the 32 valve intech v8 4v?
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Tuesday, May 15th, 2018 AT 2:18 PM
Tiny
ROY B
  • EXPERT
That is correct. It is the only engine listed.

Roy
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Tuesday, May 15th, 2018 AT 2:27 PM
Tiny
BUSINESSFRED
  • MEMBER
Okay, thank you Roy.
I hope this resolves my problem it is very concerning when it stalls on me.
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Tuesday, May 15th, 2018 AT 2:45 PM
Tiny
ROY B
  • EXPERT
I agree. Keep us updated.

Roy
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Tuesday, May 15th, 2018 AT 2:48 PM
Tiny
BUSINESSFRED
  • MEMBER
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?
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Thursday, May 17th, 2018 AT 2:28 PM
Tiny
ROY B
  • EXPERT
At the EGR valve, yes.

Roy
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Thursday, May 17th, 2018 AT 3:02 PM

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