2003 Ranger--Check Engine Light

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Jun 1, 2011 | 09:58 AM

bronco549

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2003 Ranger--Check Engine Light

My truck is 2003, V6, 4.0, SOHC. The check engine light recently came on--the code scan showed PO 171, System too lean (bank 1) and PO 174, System too lean (bank 2). My question is, what ailment in the engine would cause these readings and what can I do to fix it (short of taking it to a mechanic)? Any suggestions/comments will be appreciated.

Jun 1, 2011 | 02:25 PM

michigan66

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From: Dexter, MI

Sounds like your O2 sensors need to be replaced.

Jun 1, 2011 | 08:09 PM

powersmoked

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From: Boston, MA

Quote:

Originally Posted by bronco549

Quote:

Originally Posted by michigan66

Sounds like your O2 sensors need to be replaced.

it is not the O2 sensors. maybe MAF, vacuum leak,

Jun 1, 2011 | 08:14 PM

Rockledge

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From: Connecticut

I agree, it's more likely a vacuum leak.

The SOHC is prone to developing holes in the PCV elbow hose, allowing unmetered air into the upper intake, and hence lean codes.

https://www.ford-trucks.com/forums/6...1-codes-3.html

Jun 2, 2011 | 07:14 AM

WA4OSS

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At about 58000 miles my 2003 3.0 V6 showed this code. After several resets and re-cycles. The dealer flashed the computer with new software. There had been two updates. Now at 78000 miles the problem has not returned.

Jun 2, 2011 | 07:06 PM

bcaughhorn

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From: Grand Bay, Al

my mustang had the same problem. it was a loose hose clamp between the maf and throttlebody

Jun 3, 2011 | 10:43 AM

wp120470

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From: Smithfield N.C.

I am with powerstroked on this one do not but new o2 sensors. Vaccum leak is most likely to be the problem. Also if you cant find it, take some carb cleaner and pinpoint shoot some at the base of the intake and lower plenum and listen for a change in idle. Thats what your mechanic is going to do first.