Expedition Check Engine Light codes P0171 and P0174

I have a 1998 Ford Expedition. It has 97,000 miles on it and I have had very little trouble with it. I bought the truck new from the factory. I have taken very good care of it. After a trip on the expressway (30 mins.) I pull into my mothers driveway and the check engine light comes on. It did this a few years back and I put some gum out in the tank and the light went away. I did the same thing this time except now when I come to a stop or I am at idel, the car sounds like its missing. Even while driving the engine seems to be mis-firing. The light is now always on. When pulling a trailer or driving regular everything seems fine. Any ideas? It has stalled a few times when pulling up to a red light. I ran codes on it when I got home from my mothers and got codes p0171 and p0174 they come out to be that the fuel system is lean? Whats my first step? Thanks

-Ben Its got a ruff idel, some times rises to 1500 rpm.

Reply to
Ben Witek
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I'm normally clueless about these things, but I'd first check my fuel filters. Then I'd check to see if it was pumping gas the way it should. Those two things just rule out the obvious, in my book. Then I can start fiddling with the electronics.

good luck and let us know how it turns out.

Plasyd

Reply to
Plasyd

Could be any number of problems. There's nothing you can do except check for a clogged fuel filter, loose or corroded wiring to the injectors, pump, or PCM. If that all passes inspection, check the fuel pressure, the fuel pump, the injectors.

Reply to
Mike Sykes

Sorry, I meant to add this link to the post for the future.

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Reply to
Mike Sykes

Reply to
Steve

On Fri, 14 May 2004 09:01:43 -0700, Ben Witek rearranged some electrons to form:

Lean codes can also indicate a vacuum leak downstream of the mass air sensor. Check your vacuum and PCV hoses for rot.

Reply to
David M

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