As I mentioned in a previous post, my fiancee has a 94 Regal with 120K miles on it. The engine is the 3800 V6. I currently run Mobil 1 10w30 and was thinking of going to preferably a 10w40. I'd like to keep using Mobil 1 but, I see it is only offered as a 0w40. Any thoughts? The reason for contemplating the switch is low oil pressure at idle. The Mobil did better than conventional oil, but I'd still like to see pressures a bit better than just above "the red zone" on the guage at idle and between 38-40psi when either cruising or under hard acceleration. And yes I'm aware that the factory guages are somewhat innaccurate. So any problems changing to a 40wt? And if so, which brand since I'd prefer to stay with a 10w40 synthetic.