I bought my bronco like 9 months ago. the oil pressure gauge would always read in the middle of the word normal. Recently I put some motor flush in the crank case, and then got my oil changed. After the oil was changed the needle stays at the very low side of the word NORMAL on the gauge. Usually right by or below the N. It stays this way regardless of the engine rpms. Does anyone have any ideas? Also, is this still within the safe oil pressure range?