my problem almost seems electrical but ill post the question anyway.swapped 4.6s from a 94 cv,the first motors bearings were shot, so we used a 4.6 from a grand marquis. motor runs fine but after warm up the oil gauge drops to nothing but when i accelerate it goes to normal. but when the needle moves its jerky,mainly when i cut the a/c on. no rattling or nocking from the motor(except for a sticking lifter)replaced the pressure sensor on the filter housing but cant really seem to chase this one down. any one have a clue. oil screen is clean and the pump works good we checked it when we had the motor on the stand.