When I first start my V8 P6 from cold, the oil pressure is very good, reading about 3/4 of the way up the gauge. As it gets warm though, at tickover, it drops; this I know is normal, oil gets thinner as it warms up, but after a few mins at tickover, engine up to normal running temperature, it drops enough to just put the oil warning light on. If you gently blip the throttle, it jumps back up to about 1/2 way on the pressure gauge; the oil warning light only just comes on at tickover, with a warm engine. There are no untoward sounds from the engine, sounds silky smooth. I'm wondering if the oil pressure sender may be reading a bit low. The car ticks over at an indicated 800rpm on the tacho. I'm not overly concerned, but am uncomfortable with a warning light coming on at tickover. Is this normal??