P0174 & P0171

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Jun 16, 2004 | 11:12 PM

Davez99Expy

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P0174 & P0171

I need help!!! All I can figure out from my manual is that both bank 1&2 are running lean. But why??? I changed both O2 sensors (does that control Air Fuel mixture?) no change.
I added a K&N air filter about 4 months ago. could that be letting in too much air??? Strange that code only popped up just a few days ago though.

I'm new to this forum, thanks for any help.

Dave

Jun 16, 2004 | 11:35 PM

Davez99Expy

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P0174 & P0171

forgot to mention: 99 Expy, 5.4L, 96k miles

Jun 17, 2004 | 04:35 AM

brooks35

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It is probably the vacum line that runs to the rear of your intake manifold from the pcv valve. they tend to crack and leak tripping the lean code.Mine did the same thing.Hope this helps fix it.

Jun 17, 2004 | 04:53 AM

trike1946

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From: NJ where fun comes to die

Yeah, check the vacuum lines. I have a K&N with no problem. If no vacuum leaks, take it out for a good run, then cancel the codes and see if they return.

Jun 17, 2004 | 11:52 AM

bodu

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I had the same problem and it was the PCV elbow at the rear of the manifold. It fell apart as soon as I touched it. I replaced it with a Chrysler one from Autozone that cost under $2. Hard to get to, but a cheap fix.

Jun 17, 2004 | 03:26 PM

Racerpro

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P0171 / P0174

I had the same error codes and finally took it to Ford of Tulsa 2 days ago. It was repaired at a cost of $236.16. They replaced the PCV hose, They said it had developed a hairline crack in the hose where it connects in the back of the engine and would only fail under acceleration. I also had replaced the high dollar O2 sensors just to have the errors return. Error has not returned since repair. Hope this helps.

Ken