The effects of NO+ rotational state and collision energy on the reaction NO++C2H5OH --> HNO+C2H4OH+ were studied in a guided-ion-beam instrument over the collision energy range from 50 meV to 3.7 eV. Integral cross sections for the reaction are presented. NO+ is prepared in specific rotational levels (N+ = 0,1 and N+ = 10) by means of mass-analyzed threshold ionization. Ab initio calculations were used to probe stationary points on the potential energy surface. The reaction is sharply inhibited by collision energy, suggesting a bottleneck for reaction. If rotational energy had a similar effect, similar to 50% inhibition from N+ = 10 excitation would be observed at low collision energy. Instead, rotation is found to have no effect within experimental error. A precursor complex mechanism is proposed to explain the results.