A nonuniform equilibrium electric field oriented in the direction perpendicular to the magnetic field, and parallel to the density and temperature gradients, is considered. The effects of electric field gradients on the behavior of ion temperature gradient instabilities are examined. Electrostatic modes are considered in the local approximation for a shearless slab geometry, with phase velocities much lower than the characteristic electron thermal speed. The adiabatic response of electrons to the perturbing potential precludes the existence of Kelvin–Helmholtz (driven by velocity shear) and Rayleigh–Taylor (driven, e.g., by a centrifugal acceleration) instabilities. The velocity shear, caused by the nonuniform equilibrium electric field, has two principal effects. The first, proportional to the gradient of the velocity shear, causes both the well-known finite Larmor radius (FLR) modification to the E×B drift, as well as distortions of the particle unperturbed orbits. The second, proportional to both first and second spatial derivatives of the E×B drift velocity, shifts the cyclotron frequency, thereby modifying the effective FLR parameter, k⊥ ρi. Generally, electric field profiles with a positive second derivative in x (the radial coordinate in a slab geometry) have a stabilizing influence.