Code P0171 bank 1 lean

WILKINSONT22

MEMBER
2005 MITSUBISHI GALANT
4 CYL
2WD
AUTOMATIC
180,000 MILES

Got the p0171 bank 1 is lean. My bank 1 stft is +24.2 and ltft is +10.2 at idle. At 2,000 rpm's the stft stays at +24.2 and my ltft drops to +4. The way I'm understanding this is there might be a clogged injector. Am I right? If I'm not please point me in the right direction. The car runs and drive good. Thank you.

3 Replies

KASEKENNY

MECHANIC
18,907 POSTS

You are correct that this is saying that there is more oxygen in the exhaust then is desired so that means there is less fuel going through it (which would support your idea of an injector issue) or there is a leak allowing more air to come into the engine. The major thing we need to check is for a vacuum leak.

Here are two guides that will help with this issue. Let's run through this and report back what you find and we can go from there. Thanks

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

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Monday, June 29th, 2020 AT 2:47 PM

WILKINSONT22

MEMBER
24 POSTS

So I sprayed carburetor cleaner on everything and found the car wants to die when I am spraying the number 4 cylinder injector. Is the number 4 cylinder (left side of engine) Bank One? Also wouldn't the injector leak fuel? I don't see any leaking. Would it be a leak in the intake manifold?

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Monday, June 29th, 2020 AT 4:36 PM

KASEKENNY

MECHANIC
18,907 POSTS

You have a 2.4L, correct? If so, then you only have one bank. So if it is almost stalling when spraying an injector then it could be not sealing but that would normally cause a fuel leak. So I attached a diagram of the things around the injector. I am thinking there is something like a PCV hose or something like that around there that is pulling in the fuel. Basically something is pulling the fuel in causing it to run too rich which is causing the engine to bog down.

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