running lean

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Dec 27, 2004 | 08:44 PM

jmurphy_5

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running lean

I have 93 f150 4.9 and i get code that said that i was running lean. i replace o2 senson but code came back. what else could cause this problem. also getting poor milage. about 40 mile per tank less than normal.
thank for any help.

Dec 27, 2004 | 09:18 PM

95 F150

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It sounds to me like a vacuum leak, inspect all of the vacuum lines and use some starting fluid and spray it around the intake and listen for a change in engine rpms.

Dec 27, 2004 | 11:57 PM

Talyn

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Joined: Oct 2003

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From: Ashland City, TN

PCV Valve
check rotor for signs of electrical wear.

Clean your air filter?
:P

maybe check your throttle positioning sensor. you can do it with an ohm meter and some paper clips.

Dec 28, 2004 | 01:28 PM

MemOrex

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From: B/CS, Texas!!

What code was it? 41? It could be vacuum leaks, but those leaks could also introduce those dreaded EGR codes; 32,33,34,35

Dec 28, 2004 | 06:00 PM

mike L

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From: va

whats the code?

Dec 29, 2004 | 10:05 AM

fefarms

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Lean codes and bad mileage can be caused by a mis-firing cylinder. Any oxygen not reacted with fuel will come out the tailpipe and be regarded as "extra" oxygen by the oxygen sensor, even though the rest of the cylinders have a perfect stoichiometric mixture.

Low fuel pressure is another common cause of lean codes.