check engine light on and a newbie

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Jan 21, 2008 | 10:22 AM

scrappa1223

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check engine light on and a newbie

hi everyone. i am new to this forum so please bear with me. i recently bought a automatic 2000 ford explorer with the SOHC 4.0. it has 119,000 miles on it and has not given me any problems until recently. the check engine light came on so scanned it and came up with 6 codes. 3 of them read PO171 and the other 3 read PO174. thePO171 code says bank 1 is lean and the PO174 code says bank 2 is lean. i replaced the mass airflow sensor thinking, "what is the probability of both O2 sensors going at the same time." after a week the check engine light came back on. please help me out because i do not want to bring to the dealer. should i replace the o2 sensors, or can it be something stupid?

Jan 21, 2008 | 11:13 AM

aquanaut20

Cargo Master

Joined: Aug 2003

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From: BC Canada

Check for air leaks, intake manifold, vacuum hoses

Jan 21, 2008 | 12:37 PM

winfordr

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Joined: Jan 2001

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From: Rural Florida Panhandle

I believe it could also be faulty or sticking injectors. I would buy a bottle of the good fuel system cleaner and run it through because it's the cheapest fix (besides loose vacuum hoses) if it works.

Jan 22, 2008 | 09:55 AM

Bear River

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Joined: Nov 2004

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From: Salt Lake City, Utah

Leaks are the most likely issue, but if the engine has run rich for an extended period of time, the O@ sensors get carbon build up on the elements, and that will cause them to read lean.

Run some Seafoam through the system, and look for intake leaks. It is common for that engine to leak around the intake gaskets. If the O2 sensors have never been replaced, they probably should be for good measure, but you really need to make sure they are not intake or vacuum leaks. Those will cause a false lean that will make the truck run rich.

Jan 22, 2008 | 10:45 AM

scrappa1223

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thanks for the reply's. i also tryed doing the fuel system cleaner but did not work. today i checked for vaccum leaks for a while and could not find any, but that doesnt mean there are not any. i suspect that will be the issue though so i will search "seafoam" in the forums and see how that works. ill keep posted.

Jan 22, 2008 | 10:52 AM

antony25

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Joined: May 2005

Posts: 305

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From: Omaha, NE

Lower intake gaskets is a common problem on this engine.