My 2008 chevy Avalanche ltz won't start sometime and when it does the gages and door locks go crazy. I have saw videos on YouTube on how to fix the problem but still dont work. I have replaced the battery, alternator, starter,ignition switch, negative battery cable, pcm, bcm, added extra ground wire to the ground strap from the motor, replaced fuse box inside the truck, replaced all fuse in junction box under the hood, replaced ground wire from the hood. Still same problems. A friend told me to try replacing positive cable and cam shaft sensor. Need help asap