Autoionizing 4fng J = 0 - 3 levels of barium in the energy range 88 240 - 90 460 have been studied, both experimentally and theoretically. Excitation spectra, recorded in a three-step pulsed laser experiment based on an isolated-core excitation scheme, are confronted with eigenchannel R-matrix calculations. Series converging to the upper and lower thresholds are found to interact strongly, in particular for J = 1. As a result the observed 4fng resonances vary widely in width, shape and intensity. Although the complete R-matrix calculations involve many interacting channels for each J (up to 49 for J = 3), good agreement is found between experiment and theory and all observed resonances can be unambiguously assigned.