shawend
TYF Newbie
I have a 2007 Tahoe LT 4WD. It has 305,000 miles and is going strong. Recently I had the check engine light come on while experiencing a shudder and loss of power. Misfire was my thought which was confirmed by a p0300 code as well as a p0150 and a p0449. It had been at least a year since I had replaced the plugs, so I started with plugs, wires, and coil packs. The problem remained. I went on to address the p0150 code and replaced the upstream O2 sensor. The p0150 problem went away but the p0300 and p0449 remained. I replaced the vapor canister purge valve, but no joy. At this point I do not feel that my p0449 code is impacting my p0300 misfire condition. The p0300 is where I would like to start. I have gone over all of the vacuum lines and have not discovered any leaks. When I have my scanner connected, I am getting misfires on cylinders 2, 3, and 4. I am uncertain where to proceed. Intake gasket? Any suggestions would be greatly appreciated.
