Not a gun of mechanics but its firing at least. Sounds like somthing to do with fuel not getting through your machine maybe such as a rooted fuel pump. Benny could be right aswel. GC8 MY99/00 have gay Air Flow Meters (AFM's) and like to die alot. Whilst we are on this subject, wheres a good place to get a new AFM as i think im going to replace mine before it kills itself.