Chevrolet Repair: 6.2, service writer, diesel suburbans

Question
I own 3 6.2 diesel suburbans we use them for beach fishing, one of them is down on power,we changed all filters with no results then upon inspection of the pump we discovered that it is a California truck in which you align the two half circles to time the pump. Is this why the truck is low on power and can we do anything about it?

Answer
what year is the truck? is the fuel pump on the block, or in the tank? im not framiliar with a california truck. what i would do is call a local dealership and ask a service writer to get you the alignment procedure for that pump. if its aligned correctly and you still have a power problem, i would look into either the injectors, or an air restriction. good luck and let me know what you find.