On my 2009 Avalanche, there was an emissions sensor that went bad. I tried all the things you did, which worked for a while then the check engine light came back on. Before I took it to the garage, I lost power at the transmission - pedal all the way in, RPMs to the red and 40 mph, on a major highway. ... it was ~$800 to fix the sensor & flush transmission fluid. Runs like a champ now. Might be worth having your mechanic take a look. Hopefully it's not as expensive a repair as I had.
when I take the neg cable off it will auto start but after a few mile the code comes back and the auto start will not work code p0121
2008 Chevrolet Avalanche
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Maintenance & Repair
As long as I keep my foot on the gas it's good. As soon as I take it off power drains and it shuts off.
2003 Chevrolet Avalanche 1500 RWD
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Maintenance & Repair
My suspension is feeling rough and my right front tire will bounce even on flat surfaces
2002 Chevrolet Avalanche 1500 4WD
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Maintenance & Repair
I own a 5.3 2007 Avalanche. It has 160k miles. When it is first started it holds approx. 40 pounds of oil pressure, once it warms up, when idling it drops to 0 and the bell goes off. If I give it a li...
2007 Chevrolet Avalanche LTZ 4WD
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Maintenance & Repair
The dash keep saying service 4 wheel drive.. Is it dangerous to continue driving it?? What's the worst that can happen?? I have a road trip plan for this weekend and my mechanic is out of town
2004 Chevrolet Avalanche 1500 4WD
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Maintenance & Repair
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