been through everything on this blazer for this code but here it goes any help would be appreciated. was driving down the road fine then all of a sudden check engine light came on and rpm gauge went dead. scanned for codes and came up with the mass air flow sensor(changed) and the code p1345 for the camshaft position sensor which i also changed. but the code for the camshaft sensor didnt go out so i naturally went to the next step and replaced the timing chain and gears. but the gauge is still dead and the code is still showing. not sure where to go from here but any help would be great. thanks