My Chevy Trailblazer is sputtering in the morning, P0171 Code has been coming up?

Asked by Jul 06, 2016 at 10:35 AM about the 2007 Chevrolet TrailBlazer LS

Question type: Maintenance & Repair

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For a little over a month, P0171 (System to Lean) code comes up. My brother has cleaned the throttle and the MAF. It then worked fine for a few weeks, then the code came up again and the sputtering started. He took it to O'Reilys Auto Parts. They had said since you removed the trottle and put it back in, it would need to retrain itself. He then removed it again and cleaned out other parts in the car. Just the other day, my car started sputtering again in the morning. It runs fine the rest of the day. Also, when I was out of town the other day, my car sat for about 4 days with a low tank of gas. When we were traveling on the highway, my reduced power engine light came on. Once I filled up with gas it was fine. i am just trying to see what could be the problem. Do I need a new O2 sensor, a change of the manifold gasket, fuel injector cleaning... Not sure. The car is good to drive, but would like to fix this problem.

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I had the same problem on my trailblazer, having made a complete diagnosis of pcm and have everything cleaned and remplcé the probe that returned code (P0171) accordingly I checked the operation of the electronic control with manual 'vehicle workshop. It turns out that the injection time is controlled in proportion to the engine temperature. So I tested the temperature sensor (new) and me have noticed that the resistance of this one was 3486 ohms to 371 ohms cold and hot (90 ° Celsius). The specifications of the CFM indicated information received should not be-lower to 470 ohms, 371 ohms to the impoverishment of the mixture is such that the pcm can fix it. Solution I have developed: I installed a variable resistor with a value of 10 to 100 ohms bridged in series on the circuit of sencor (it's very easy to do: cut the black wire upstream of the outlet and is welded this resistance), then with an ohm meter, I rule this resistance to 78 ohms which gives me a total value of 449 ohms hot (90 °). I started my engine and deleted fault codes (po171 and p0138) since this code is not income, and missed more unstable idling and over mistfire. It is imperative to use a variale resistance that can adjust ave a screwdriver to the LIB Leplus possible end setting including the setting of pollution.

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