We report sensitive imaging observations of the CO J=1–0 line emission in the powerful high-redshift radio galaxy 4C 41.17 ( z = 3.8 ) with the NRAO Very Large Array ( VLA ) , conducted in order to detect the large concomitant H _ { 2 } gas reservoir recently unveiled in this system by De Breuck et al . ( 14 ) via the emission of the high excitation J=4–3 line . Our observations fail to detect the J=1–0 line but yield sensitive lower limits on the R _ { 43 } = ( 4 - 3 ) / ( 1 - 0 ) brightness temperature ratio of R _ { 43 } \sim 0.55 - \ga 1.0 for the bulk of the H _ { 2 } gas mass . Such high ratios are typical of the high-excitation molecular gas phase “ fueling ” the star formation in local starbursts , but quite unlike these objects , much of the molecular gas in 4C 41.17 seems to be in such a state , and thus participating in the observed starburst episode . The widely observed and unique association of highly excited molecular gas with star forming sites allows CO line emission with large ( high-J ) / ( low-J ) intensity ratios to serve as an excellent “ marker ” of the spatial distribution of star formation in distant dust-obscured starbursts , unaffected by extinction .