The special injection molding process GITBlow, developed by Polymer Engineering Paderborn (KTP), combines the respective advantages of the established processes of gas-assisted injection molding (“GIT”) and blow molding (“Blow”), thereby creating new process with new economical benefits compared to conventional hollow space forming processes. The direct GITBlow process creates a large, thin-walled hollow space by pulling a core inside the mold to enlarge the cavity of the preform. The preform is produced via gas-assisted injection molding and is then further inflated via a second gas injection. Parts produced with the direct GITBlow process can be used for media lines, wire ducts or tank components. A homogeneous wall thickness distribution is necessary for these applications. This part property is dependent on the inflation behavior of the part during the second gas injection, which in turn is influenced by the temperature distribution in the residual wall of the preform. In this study an operating point is determined by variation of the process times, the injection pressure of the gas and the temperature control of the mold. The influence of the varied parameters on the temperature distribution in the preform wall is analyzed. It is shown, that the preform properties which are established in the first few seconds of the production cycle, have the biggest influence on the resulting inflation behavior of the part. Subsequently a guideline is developed for the approximate optimization of the operating point, especially concerning the required parameter settings for the first gas injection.