Line coupling induced by collisions leads to drastic modifications of the spectral profile of the 00(0)3-00(0)0 of CO2 pressurized by helium. Calculation of these modifications have been performed by using two recent energy corrected sudden (ECS) formalisms. The two formulations lead to theoretical predictions rather similar and in good agreement with the available data over extended ranges of frequency and perturber pressure. It has been shown that a simultaneous fit of the pressure broadened linewidths and the near wing profile allows a more accurate determination of the basic ECS parameters. For that purpose, it has been necessary to extend the measurement of the broadened widths to high J values (up to J approximate to 90).