The hoses/clamps are "supposed" to be inspected/changed every 30K I believe. On the injector recalls we did on the Z31/max's the proper way to tightend the fuel line clamps with new hoses was to be able to put a dime in the clamp after tightning it. In other words tighten the clamp untill the gap in the open part of the clamp is the width of a dime. This is using the strap style "nissan" clamps. If you ask at most nissan dealers for "dime" clamps they will know what you are refering to.