Codes p0171 and p0173 lean codes
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Joined: Oct 2009
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From: Olathe Kansas
Codes p0171 and p0173 lean codes
I have a 02 5.4 4x4. Getting lean codes. They always come on at the same time. And usually only when it's cooler outside. I've checked some vacuum lines. The Pcv elbow is new along with the Pcv valve. Checked the vacuum line on the back of the throttle body. Have a hard time believing its 02 sensors. But there looks like a wet/ or greasy spot to the left of the alternator at the intake.
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I have a 02 5.4 4x4. Getting lean codes. They always come on at the same time. And usually only when it's cooler outside. I've checked some vacuum lines. The Pcv elbow is new along with the Pcv valve. Checked the vacuum line on the back of the throttle body. Have a hard time believing its 02 sensors. But there looks like a wet/ or greasy spot to the left of the alternator at the intake.
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Joined: Jul 2010
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From: Alaska
Have you tried using a good can of carb cleaner to chase down the vacuum leak? Usually a vacuum leak with those 2 codes or dirty MAF. Berryman B12 or another good brand can find a leak in seconds. When the engine picks up rpms (with B12 anyways) you've found your leak area. You can then find the exact spot and change the broken piece of hose or item that is causing the leak. Check the vacuum line to the brake booster, as well as the booster also. The check valves in the older trucks would leak, setting codes. A rusted booster can, can cause a vacuum leak from the diaphram. Just some thoughts for you to consider.
As in the old commercial for Chex, "Try it, you'll like it". lol
As in the old commercial for Chex, "Try it, you'll like it". lol
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Joined: Mar 2013
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From: Western Canada
Funny you should mention checking the gas cap. I have these same codes coming up on my 98 with a 4.2, done all the same checks as everyone else it. I read on another forum that these codes could be a indication on a fuel pump on its way out. I had one pump on my other 2000 go and it didnt throw any codes. Any thoughts on if a weak fuel pump could cause these codes.
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From: Montgomery County, Maryland
It could be as simple as the clamp on your airbox not properly tightened thus allowing more air into your airbox, or the rubber grommet at the bottom of the airbox connected to MAF not inserted flush thus also allowing more air also. This was exactly my problem with these codes.