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Check engine light came on?

Tiny
RICHARDTAYLOR
  • MEMBER
  • 2002 FORD EXPEDITION
  • 150,000 MILES
Check engine light came on after codes says it is banks 1 an 2 running lean?
Sunday, December 9th, 2012 AT 11:00 PM

37 Replies

Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
I need the exact code numbers this guide can help us get the codes.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.
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Sunday, December 9th, 2012 AT 11:17 PM
Tiny
RICHARDTAYLOR
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  • 5 POSTS
5.4L an the code were p0171 an p0174
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Sunday, December 9th, 2012 AT 11:41 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Have you checked for a vacuum leak yet? That's where i would start. This guide can help.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please run down this guide and report back.
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Sunday, December 9th, 2012 AT 11:43 PM
Tiny
RICHARDTAYLOR
  • MEMBER
  • 5 POSTS
Thanks for the guide I found the PCV hose had a big hole in it si I got a new one and cleared the codes and it has not come back. Thank you this site is amazing!
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Sunday, December 9th, 2012 AT 11:48 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Use 2CarPros anytime, we are here to help. Please tell a friend.
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Monday, December 10th, 2012 AT 12:23 AM
Tiny
RICHARDTAYLOR
  • MEMBER
  • 5 POSTS
I will thanks for your help
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Monday, December 10th, 2012 AT 12:38 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Just to add, there is a vacuum behind the throttle body on the pcv line that is common for collapsing and causing the lean codes, is this the one you replaced?

Roy
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Monday, December 10th, 2012 AT 1:50 AM
Tiny
RICHARDTAYLOR
  • MEMBER
  • 5 POSTS
Yes that was the first thing I checked and replaced
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Monday, December 10th, 2012 AT 2:05 AM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Good to hear, please use 2CarPros anytime we are here to help.
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Monday, December 10th, 2012 AT 3:20 AM
Tiny
LISSABABE123
  • MEMBER
  • 1 POST
  • 2002 FORD EXPEDITION
  • V8
  • 4WD
  • AUTOMATIC
  • 190 MILES
Im trying to get my check engine light to turn back on so I can replace one of the bad coil packs. I went to the shop and they told me which one it was. I replaced it and not even a week later another was bad. How do I get the light to turn on in order to find out which one it is without going to a shop?
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Wednesday, November 11th, 2020 AT 1:09 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
HI there the ECU must recognize a fault with in the parameters of the engine management system before a check light can be set, trying to induce a code will not give you a true indication as to what the problem is.

Mark (mhpautos)
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Wednesday, November 11th, 2020 AT 1:09 PM (Merged)
Tiny
NARMSTEAD
  • MEMBER
  • 3 POSTS
  • 2001 FORD EXPEDITION
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 232,000 MILES
My alternator went bad and I replaced it two weeks ago, a few days later check engine light came on got the code p0306. It started chugging while idling, wipers have slowed down, shaking when accelerating.
Have changed thermostat due to it was slightly leaking, replaced cylinder six plug, plug boot, ignition coil, PCV valve, EGR sensor, EGR connector, replaced vacuum lines that were bad.
I'm at my whits end here!
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Wednesday, November 11th, 2020 AT 1:10 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
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Good evening,

You covered most of it except for compression and the injector.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Do you have a noid light to see if the injector is commanded on from the PCM? You can rent one at a parts store if you do not have one.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

I would definitely check the compression.

https://www.2carpros.com/articles/how-to-test-engine-compression

Roy
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Wednesday, November 11th, 2020 AT 1:10 PM (Merged)
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
Common failures on these trucks is the intake leaking coolant into the plug holes. I would remove the other coils and inspect for coolant contamination. If the concern is only while accelerating, this is where I would start looking.
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Wednesday, November 11th, 2020 AT 1:10 PM (Merged)
Tiny
NARMSTEAD
  • MEMBER
  • 3 POSTS
We have a multi-meter and we will test that tomorrow. Headed out soon to do the screwdriver test.
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Wednesday, November 11th, 2020 AT 1:10 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Please be careful. There is a lot of spark from the coil.

Roy
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Wednesday, November 11th, 2020 AT 1:10 PM (Merged)
Tiny
NARMSTEAD
  • MEMBER
  • 3 POSTS
Husband is an electrician and a mechanic best of both worlds.
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Wednesday, November 11th, 2020 AT 1:10 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
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Okay, let us know the results.

Roy
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Wednesday, November 11th, 2020 AT 1:10 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
  • 2001 FORD EXPEDITION
  • 144,000 MILES
4.6L engine will start to sputter when engine comes up to operating temperature. Check engine light never came on. Vehicle never stalls.
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Wednesday, November 11th, 2020 AT 1:10 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Most likely plugs and coils.

Ford has expanded there parameters to not have the light come on till it is a dead miss for a while

Roy
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Wednesday, November 11th, 2020 AT 1:10 PM (Merged)

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