Bad EGR Valve?

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Nov 20, 2006 | 10:28 AM

wezol5484

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Cargo Master

Joined: Sep 2003

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From: TX

Bad EGR Valve?

I think I may have a faulty EGR valve. Its dying sporadically, but only at idling RPM's or anything below a grand. The codes its pulling are 171 and 174 but I replaced one of the 02 sensors about 10K miles ago and I think the odds of both of them going out at the same time are too slim. There are no vacuum leaks (fixed those) and I have a new IAC.

If its worth anything, I have no main cats and have simulators for the rear 02 sensors but from what I understand those have nothing to do with the mixture.

So could a faulty EGR (or clogged) throw those codes?? I have run out of ideas and starting to run out of money. The problem has been going on since last December but I have been gone from July through yesterday, so I have just now had a chance to get back on the problem.

Any ideas would be very appreciated.

Nov 20, 2006 | 06:20 PM

Bluegrass 7

Lead Driver

Joined: Sep 2006

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You sure like punishment.
Look over all the intake hose areas for cracks or any fault that lets air in from the mass air meter toward the engine.
All smaller hoses at all locations.

Nov 21, 2006 | 10:12 AM

wezol5484

Thread Starter

Cargo Master

Joined: Sep 2003

Posts: 2,735

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From: TX

I looked for a very long time for any vacuum leaks. The PCV hose had a hole where it bends into the throttle body and the gasket for the IAC was leaking as well. I repaired both of those and have gone over all the vacuum hoses many times over to no avail. It acts like a vacuum leak, but I don't hear anything (anymore) and cant for the life of me find anything else. I'm freaking stumped. I'll go out and look again for grins, maybe I'll get lucky and find something.

Any other ideas on what it could be though???

Nov 21, 2006 | 11:18 AM

KingRanchMan02

Posting Guru

Joined: Oct 2005

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From: Louisville, Kentucky

Take a look at the recommendations on this website.

http://www.obd-codes.com/trouble_cod...gen-sensor.php

Last edited by KingRanchMan02; Nov 21, 2006 at 11:21 AM.

Nov 21, 2006 | 06:42 PM

Bluegrass 7

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Something that might be of help is to reboot the PCM.
Since you run so long with the fault, the PCM has attempted to shift it tables trying to correct for the problems.
The only way to reset them (tables) back to neutral calibration is to reboot and let it find the new setting due to the repairs.
Remove power from the PCM for about 15 minutes to be sure it happens.
Expect a different feel until it re-learns.

Last edited by Bluegrass 7; Nov 21, 2006 at 06:44 PM.

Nov 21, 2006 | 08:52 PM

LxMan1

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Joined: Dec 2001

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From: Louisville,Ky.

You might also clean the MAF.

Dec 3, 2006 | 01:03 PM

navymadjew66

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Joined: Dec 2006

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I think Im having the same problems that you are except im not getting any codes. I can drive at highway speeds just fine but once I slow down using the brakes, engine and transmission slow me down it dies once it reachs 15 and below. Is this sound familiar.