Please Help 92' Eagle TSi AWD

ok so i took my car in today and they said they were concerned with the cooling system because it was overheating or close to it, and also that once warmed up my oil pres. gauge is sitting at zero. Now when i am Idling it is either at 0 or slightly above. But if i just tap the gas it will max out my oil pressure gauge at 100 but it burys the needle. please help my diagnose this problem before I take in onto the shop again.

id replace your oil pressure sender,if it is an electric sender.if you had bad iol pressure it would not go to 100.