Disclosed are a method and apparatus for minimizing or eliminating the effect of air gap variation on the output signal of a magnetostrictive stress/torque signal. An RLC drive circuit is utilized by choosing appropriate circuit parameters and drive frequency such that the flux reducing effect from increasing air gap due to increase in magnetic reluctance is offset by a flux increasing effect from a concomitant reduction in eddy currents. The invention is particularly suited to cross design magnetostrictive sensors and to automotive engine diagnostics applications such as misfire, knock, and roughness detection.