Just bought a 2007 Chevy Avalanche with 140k on it. Got a good deal (I thought) and it is in pristine condition. Until I started getting the codes. The first to pop up is the P0420 bank 1 catalytic efficiency code. I have since replaced the cats (Walker one piece y assembly), the downstream o2 sensor on driver side, changed plugs and wires (OEM), sprayed carb cleaner around intake to check for leaks, cleaned MAF sensor with MAF cleaner spray, compression tested cylinders (all cylinders tested between 190 and 205). Each time, i disconnected the battery to clear codes and the codes come back after a few hundred miles. I drive 200 miles a day for work. The P0420 code is always coming back but sometimes I get P0137 (bank 1 sensor 2 o2 sensor low voltage, p.s. i already changed that one and still get code, connections good with dielectric grease) and P0171 system too lean bank 1. There is some oil consumption but I believe it is due to the AFM. Had a couple cold days that it blew out a good size puff of blue smoke on start up but on warm days or running, there is no smoke. I'm at wits end with this thing. There are no codes about a misfire so I don't believe it's a coil, fuel injector, fuel pressure regulator, or the like. So i guess my concerns now would be bad valves or maybe a jacked up cam??? I don't know how to do a leak-down test. Any ideas?

 

Check the wire harness under the trucks front driveshaft my harness got cut up after it fell and was hitting driveshaft

 

hello, Patrick France, I want to know what model of catalytic exhaust approved standards for France, for chevrolet avalanche 2003 4wd, is that I can order on the site "rockauto.fr" thank you for your help.

 

hello, Patrick France, I want to know what model of catalytic exhaust approved standards for France, for chevrolet avalanche 2003 4wd, is that I can order on the site "rockauto.fr" thank you for your help.I would like to install a sport exhaust makes a little noise but not too much

 

Need some suggestions..
My 07 avalanche drives fine then out of nowhere engine light comes on and traction control engages and doesn't disengage until I disconnect the battery and reconnect it..
Thanks