For some years there has been a dispute concerning the appearance energy of CF3+ from CF4 [AE(CF3+/CF4)], or alternatively, the ionization energy of CF3[IE(CF3)] or the heat of formation of CF3+[Delta(f)H(CF3+)]. In an earlier work [M. Tichy, G. Javahery, N. D. Twiddy, and E. E. Ferguson, Int. J. Mass Spectrom. Ion Processes 79, 231 (1987)] the reaction between HCl+ was used to support a low value, AE(CF3+/CF4)=14.2 eV. A remeasurement of this reaction over the temperature range 173-500 K shows that the original study was in error, both in the reported rate constant and the ion product. In the present work, the rate constant was found to be collisional, producing HCF4+. The rate constant for thermal decomposition of HCF4+ into HF+CF3+ was measured in the course of this work. These new measurements bring into harmony AE(CF3+/CF4) obtained from the HCl+ reaction and the value AE(CF3+/CF4)=14.67+/-0.04 eV reported by R. L. Asher and B. Ruscic [J. Chem. Phys. 106, 210 (1997)]. (C) 2003 American Institute of Physics.