02 lesabre 3.8 oil light /fuel gauge problem

have my 02 lesabre, oil presure drops to 2 and soemtime zero and at the same time the fuel gauge goes to full. oil light coems on. im not sure what the problem is. 8 times out of 10 it works fine with oil presure 60-62 psi at idle and drops to 50 or so while driving. am i missing something, seems like 2 problems but they both started to happen at the sametime./ when i notice the gas gauge slowing going to full i look at the oil pressure and it is dropping like a rock.
please help
scott

3.8 series II