random codes 0171 and 0174
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Cross-Country
Joined: Apr 2002
Posts: 71
Likes: 0
From: Houston USA
random codes 0171 and 0174
2016 6.2L with 86,000 miles ran perfectly until 2 weeks ago when I filled up with Chevron 87 octane. Within 2 miles of leaving the station the engine started to bog, surge and rattle under light accelaration. I figured bad gas. Put in some 104 octane and truck seemed to run better. Filled up yesterday with Exxon 87 octane and still getting engine rattle under light acceleration and a very random code 0171 and 1074. Cleared the codes but they keep popping up very randomly, maybe once every 3 or 4 days. clear them and they go away for a few days, .. BTW this truck has run flawlessly on 87 octane since day one...
Thoughts ? suggestions ?
Thoughts ? suggestions ?
Laughing Gas
Joined: Dec 2019
Posts: 896
Likes: 255
From: San Diego, CA
Both banks running lean, you have a good possibility that something upstream is causing it. I would do a very good check for cracked hoses that lead to the intake, loose connections on hoses and intake, etc. Even check your oil fil cap. You most likely have a vacuum leak somewhere which is causing unmetered air to get in past the MAF. If everything checks out, might want to clean the MAF just in case it is sending a faulty signal.
Fleet Mechanic
Joined: Oct 2017
Posts: 1,704
Likes: 164
From: Southwest Ohio
Monitor the upstream O2 to see if it’s switching slow. I just replaced the upstream bank 2 sensor on an Ecoboost Explorer that was causing a lean DTC due to a lazy O2 sensor. You’ll need a good scan tool or Forscan to watch the activity in graphing mode (which is easiest, IMO).
— Dave
— Dave
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rcknrbn
2009 - 2014 F150
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Aug 30, 2018 04:35 AM
