I still have the stock gauge in my 90 gt and it reads between the o and the r in the normal range. I had an 88 lx in the past and the sending unit to the gauge went bad. The gauge dropped to zero while driving down the interstate one day and I pulled over as soon as I could thinking that the engine was going to start knocking but then I realized it was the gauge. A lot of people will tell you to put a good aftermarket gauge in the car but if you like the looks of the factory one then just try a new sending unit first.
Oil pressure will change some on the gauge as the rpms increase. Passing situations will cause this . Oil pressure will also be higher on the gauge when you first start the car because the oil is thicker when it is cold causing greater pressure. As the car warms up and depending on the internal condition of your engine such as excessive clearance from wear the oil pressure will either drop a little or alot. Oil pressure will always be lower at idle than at higher rpms.
Last edited by EagleAutosports; 10-06-2007 at 10:53 PM.