The Fermilab Main Injector is a new 150‐GeV proton synchrotron, designed to replace the Main Ring and improve the high energy physics potential of Fermilab. The status of the Fermilab accelerator complex upgrade will be discussed. Study of the stability of the beam in the Main injector will be discussed. Detuning and corrector schemes to improve the dynamic aperture of the Main Injector will be presented. Tune modulation caused by octupolar detuning will be discussed.