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This paper presents an analysis of [Fe IV] emission based on newidentifications and previous measurements of [Fe IV] lines in 30 Doradus, IC4846, M42, SMC N88A, and SBS 0335-052. The Fe abundances obtained by adding theabundances of the relevant Fe ions (mainly Fe^{++} and Fe^{3+}) are found to belower, by factors in the range 2.6-5.9, than the Fe abundances implied by [FeIII] emission and an ionization correction factor derived from ionizationmodels. The most likely explanation of this discrepancy is that either thecollision strengths for [Fe IV] or the Fe ionization fractions predicted bymodels are unreliable. The available data neither allow one to distinguishbetween these two possibilities nor to exclude another possible explanation:that the discrepancy implies the presence of a gradient in the Fe abundancewithin the ionized gas. Further measurements of [Fe IV] lines and checks on theFe^{3+} atomic data and ionization models are needed to reach a definitiveconclusion. The discrepancy introduces an uncertainty in the determination ofFe abundances in ionized nebulae. This uncertainty has implications for ourunderstanding of both the evolution of dust in ionized nebulae and the chemicalhistory of low metallicity galaxies.Comment: 23 pages, 3 figures, accepted for publication in ApJ, a new table and  several comments adde

[Feiv] Emission in Ionized Nebulae