so i recently purchased a beautiful 2005 nissan pathfinder. it friggen loaded and looks like no one has driven it , i mean pristean inside and out 105000 miles on it. so it has a 6 cylinder runs good but seem like its holding back and vibrates at stops.. i was thinking catalytic converter for this issue. the other is that at stops the oil pressure gauge drops down. before you say check the oil level i have, its good. this is my first nissan and i really like it so i want to get the opinion of people who have experience with the vehicles. thanks in advance