Search this site, or try
http://www.forum.planetisuzoo.com/ -or-
http://www.4x4wire.com/forums/ubbthreads.php?Cat=&C=15 and you will see this is a very common issue with 1998-2000 rodeo V6's. The electrical contacts on the fuel tank sending unit loose good contact (the wiper & board), which causes your fuel gage to not function properly & causes the CEL to light up. You have to pull the gas tank to remove the sending unit to fix this. You can bend the contacts back together, or replace the whole sending unit. Either fix will last about the same- about 30-50Kmi. This issue was resolved for 2001+
G/luck
Joel