Low oil pressure at idle only, will most often mean that the engine is low on oil. As more power is applied to the engine via acceleration, the pressure builds up inside the engine. Thereby causing the pressure to read as "normal". High oil temperature can cause low oil pressure. A defective oil pump can also lead to low oil pressure at idle. Oil sending switches are subject to wearing out. When that happens, one possible result is that it will show low oil pressure. If your car has a light rather than a gauge, don't rely on it, because the light can fail.