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2003 Ford Expedition 5.4 p0171

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30 Jun 2020 22:53 #41022 by Thatboiiharris
2003 Ford Expedition 5.4 p0171 was created by Thatboiiharris
Smoke tested already I couldn’t find any leaks other than the idle air control valve which has been replaced new iac still seems to have smoke coming from it I’m guessing it’s normal and swapped both 02 sensors from bank to bank still no change
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30 Jun 2020 23:07 #41023 by Thatboiiharris
Replied by Thatboiiharris on topic 2003 Ford Expedition 5.4 p0171
Also put a vacuum guage to it got 20inhg and pinched off brake booster
And used a known good maf still no change in fuel trims

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01 Jul 2020 14:20 #41033 by Cheryl
Replied by Cheryl on topic 2003 Ford Expedition 5.4 p0171
Possibly a restricted cat because one bank is lean and one is rich. Have you checked fuel injector flow rates bank to bank

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01 Jul 2020 16:24 #41036 by Thatboiiharris
Replied by Thatboiiharris on topic 2003 Ford Expedition 5.4 p0171
I did an injector balance test all of them drop 13 to 15 psi each

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01 Jul 2020 18:03 #41038 by Cheryl
Replied by Cheryl on topic 2003 Ford Expedition 5.4 p0171
Did you check for an exhaust restriction?? With one bank rich and one lean I’d suspect it

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06 Jul 2020 19:55 #41123 by Thatboiiharris
Replied by Thatboiiharris on topic 2003 Ford Expedition 5.4 p0171
I did a vacuum test since I don’t have a back pressure tester it had 21inhg of vacuum at 2500 rpm

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06 Jul 2020 21:05 #41126 by Cheryl
Replied by Cheryl on topic 2003 Ford Expedition 5.4 p0171
Any TSBs? How’s it drive low on power??

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