I have a couple questions about the oilo pressure in your 199x Suburban with the 5.7 Vortec... The gauge always seems to read low to me. When she is cold the pressure till get to just below 40. Once she is warm, the idle pressure is at 19psi and when I am accelerating it gets to around 30psi. After a long highway run the pressure can drop to just above 0 and the 'check gauges' light will come on unless I give it some gas. I know this is not normal behavior, but the engine is running fine no misses, temps are below 200, etc. Since my gauge cluster is starting to get flaky I am wondering if this is just a symptom of faulty gauges (oil reading low) or if it could be a real problem, Has anybody had to change their oil pump on this engine? Has anybody tapped in a separate oil gauge? If so, where can I tap into? I started running 5w40 Turbodiesel Mobil 1, up from 5w30 gasser M1, and it seems to be helping (my other car is a Diesel) The engine only has 159k on it. has lots of power and is not blowing any smoke like it would if the rings or valve stem seals were worn out. She has only been given M1 since new and does not use any appreciable amount of oil between changes Thanks guys!