Hey all, my check engine light came on yesterday on my drive home from work so I swung by Autozone and had the codes pulled. Turns out the PCM was holding 2 instances each of P0171 and P0440. Do you all think it's a coincidence that they both turned up at the same time or is there something that might throw both codes?

I have been getting an intermittent, almost seasonal, "Check Gas Cap' message which relates to the P0440 . Even though the message tends to go away on it's own after a while, I did actually replace the gas cap a few hundred miles ago which was when I last got this message.

Using the search I didn't really find anything on the P0171, but the slip from Autozone says it might be a defective O2 sensor. I drive relatively conservatively but there have been a few times I'd throw this code (well, an O2 code at least) when I'd mash the pedal down but it'd clear itself a day or so later. This sensor hasn't given me any real trouble and has been in for roughly 1-1/2 years

Thoughts anyone?

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2000 Bonneville - SSEI

P0171 - Fuel Trim System Lean Bank 1

Check your vacuum lines around the engine, they tend to crack and dry out after time. You could be taking in un-metered air somewhere.

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2009 G8 GT - White Hot


FMS Custom Cam, Yank 3600 SS, 1LE (ZL1) 3.91, SLP Longtubes, Magnaflow cat-back, Rotofab CAI, tuned via HPTuners
415/391

Agreed, check vacuum lines, I had the same code when I had a leak in my EGR tube. So be sure to check that as well.

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Mods, CAI, Gatorback SC belt, 180 deg. thermostat, sparkplugs 2 colder gapped @ .050, 3.1" MPS, intense™ PCM, AeroForce scan gauge, Flowmaster series 80 muffler, 3" Magnaflow cat , INTENSE™ Street/Strip Performance Shift Pak, 1.9:1 roller rockers, Oil Restricted pushrods, CompCam #105 springs, CompCam heavy duty spring retainers and valve locks, 17" wheels, 245/45 FirehawkGT tires,slotted rotors, cermaic pads, Wideband O2, MSD Blaster coils, MSD 8.5mm sparkplug wires, Stainless steel TOG headers, HP tuner, P&P LIM and supercharger, SSIC
Getting ready to install cowled hood, Project on hold!
Objects in mirror are loosing!

X3 on checking the vacuum lines.

Also, just for kicks, check to see how close to a spark plug wire your primary O2 sensor wire is. Keep them as far apart as possible to eliminate electrical interference as a possible cause.

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White Horse. 230K miles, It just keeps on kickin'

Very good point, and something I need to check after work.

_________________
2009 G8 GT - White Hot


FMS Custom Cam, Yank 3600 SS, 1LE (ZL1) 3.91, SLP Longtubes, Magnaflow cat-back, Rotofab CAI, tuned via HPTuners
415/391