I changed the oil yesterday and I used a Fram Wearguard oil filter for the fisrt time as well as Kandall semi-synth 10W30 oil. I noticed a drop in oil pressure right away to the rate of 3-4 PSI while driving and almost 8 to 10 PSI at idle. I doubt that the oil is the culprit but could an oil filter cause this kind of pressure drop? I get around 40 PSI now in normal driving conditions and it drops to 20 PSI at idle. Is this an acceptable oil pressure range or should I go back to my old brand of oil filter? Thanks in advance for you inputs!