How bad is it to put injectors in a lb7 I put a new pump on it 4 months ago it was so bad it wasnt hardly giving it enough fuel to run so now with 300,000 miles on it she needs injectors. it smokes really bad and has a miss at a idle so its injector time I work on cat cummins and detroits but havent been into a duramax just wondering how bad it was to do and any special tools that I may need do you have to replace the inj, cups ect. ect.