both banks lean and fuel trim
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both banks lean and fuel trim
The SES light came on on my 03 F150 5.4L today for both banks lean P0171 and p0174 I believe. I plugged in the superchips from the bosses 7.3 to pull the codes and to look at the fuel trims. here are the trims; it starts out at idle and then after a few seconds I put some throttle in it for a bit, and then let it idle back down. What do you guys think I need to look at first?
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I just went through this fiasco trying to find the cause of high LTFT's......check it with a propane torch and a length of hose. Check all around the edge of the intake manifold gasket area's where the injectors are. If the short term trims level out then that is your leaks. My leak was so small that it was bearly detectable. Changed the manifold gaskets and all is well. It is a pretty easy job. And use Felpro Perma-seal gaskets. They are thicker and seal better around any imperfections. Good luck.
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MarkNtennessee
1997-2006 Expedition & Navigator
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10-12-2010 03:59 PM