First of all just wanted to say what a great site this is . I've been browsing in here for some time now and its become obvious that I don't know as much as I thought I did when it comes to oil's. With that out of my way here is my problem. Yesterday while stuck in traffic I caught a blink on the dash out of the corner of my left eye. Didn't know what it was at first since it went right back out. Well I started fooling around and to my horror realized that it was my oil pressure light . I could only get it to blink on if I turned on the A/C which of course drops the idle rpms just a hair. Even then the light would "stutter" on and off. Any increase in RPM's and it stayed off for good. Scary. I'm about 100 miles into my AutoRX rinse running Penzoil 5W-30W, car wasn't hot, ambient temp was probably around 75 degrees. Generally I run Amsoil 5W30 with an Amsoil filter, but after doing some research here it seems like that is too light and I maybe I should consider running 5W-40. The car is a '96 Impala SS W/LT1 and it has 130K on it. I bought it with about 75K on the clock and now I'm starting to wonder about the previous owners maintenance practices. My first thought is my main bearings are worn and out of spec. Any suggestions on what oil to run? Keep in mind down here it gets hot, really hot, in the summer and idling in heavy traffic is going to be the norm. Thanks for the help!