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1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks

Code 172 and 334

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Old Jun 21, 2009 | 12:02 PM
  #1  
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Brad_9876
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Code 172 and 334

Hey guys, I just ran a test on my 96 f250 5.8 and I got these codes out. From the book I have, they translate to 172- Ho2S Sensor fault/lean and 334- EGR closed valve voltage high. Is my O2 sensor and EGR junk or is there something else wrong? Any help is appreciated

-Brad
 
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Old Jun 21, 2009 | 12:11 PM
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alxsnmr
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From: St Louis
The EGR valve may not be closing all the way, which could in turn throw the lean O2 sensor code. I would start with EGR valve and correct that before moving on to the O2.
 
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Old Jun 21, 2009 | 12:16 PM
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I know its a stetch but could this in turn make my truck start hard when its been running? When I go to restart it it cranks forever and finally starts and blows a cloud of black smoke. My question is, if its causing a lean code, will the computer try and correct it causing it to run too rich and not want to start? Like i said, a stretch
 
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Old Jun 21, 2009 | 12:39 PM
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From: St Louis
It is possible but I would check your fuel pressure regulator is working properly with a fuel pressure test, and make sure there isnt any fuel on the vacuum side of the regulator.
 
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Old Jun 21, 2009 | 12:44 PM
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I just replaced the regulator a week ago with the hopes of that solving my problem too. I can't get any more suggestions past that
 
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Old Jun 21, 2009 | 12:50 PM
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alxsnmr
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From: St Louis
Then work the EGR over to get it functioning correctly. Once it is fixed, clear the codes and pull them again. Also, check your timing to see where it is set. Recommended setting is 10 degrees BTDC with the spout connector removed on a warm engine (at operating temperture). When was the last time you did a full tune up of your motor?
 
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Old Jun 21, 2009 | 01:44 PM
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Its all been within a year. Plugs,wires,coil.fuel pressure regulator, fuel filter, air filter, cap, rotor, and my timing is set at 12 degrees for a little more response. Im sure im forgetting more
 
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