GF has a chevy blazer with the 4.3L V6. It has 170k miles but it's still in darn good shape, considering. Drives around town great, and has lots of pep. She wasn't real good with maintenance so I took it to the shop and had them replace all the fluids (oil, t-case, trans, front/rear diffs). We didn't notice this prob before (but it may have been there, not sure): Oil pressure guage reads approx 60psi on a cold morning start, and stays around 40psi when warm and driving around. If you idle for a while at a red light or drive through the oil press guage will sit around 30psi and move back and forth a few millimeters. Is that normal? I know oil pressure at idle will be less than when driving, but shouldn't it settle at a constant pressure? It's fluctuating and that bothers me. Am I just being anal, or is this a precursor to a bigger problem?