That's great news, Nick! Many C5 guys throw in a can of Techron every 6 months or so. It helps prevent the dreaded fuel gauge going wild syndrome. Some even allow their engines to pull in Seafoam to the intake while the engine is running (until it stalls). They then let the engine sit for a night and upon firing it up, see a huge white cloud come out the pipes. This method more directly cleans out the carbon buildup on the pistons, which is caused by blowby oil going past the PCV line and into the intake.

Dave