My guess would be a wiring problem, eg, dirty connector, frayed wire.

Edit: Wiring diagrams, harness routing, etc are in the FSM if you want to do your own troubleshooting. Link in my sig.

Thanks again!! If I find anything out I will post in case someone else runs into a similar problem.:icon17:

Just a thought here. You could get an ODBII reader and sense the temperature without replacing the gauge. See if it really is the gauge or the sensor. You would really only need to get an ODBII dongle and an app for you cell phone to test this out.

I have the OBDLink MX and use Torque pro with the Nissan specific addin software. I can pull all kinds of sensor data including Oil Temp.

I figured its worth a shot before you buy the new gauge.

Just saw the last post and thanks for the input. Well guess what, no problems since replacing battery with pricey good one and discharging system as was posted on this thread-the safe way. Just found a 350z with 38,000 orig miles , no accidents, 2 owners, Florida car, but dealer wants $15,500 for it. Got him down to $13,300, but it seems like too much and it's auto, really looking towards the manual. Have'nt found one in any where near this shape. They're usually totally ragged out. Thing is they just got the car in on trade and I happened upon it while walking the back lot and saw it (my car was in for an oil change btw) and I usually take a walk back there to see if they have any goodies back there. Any thoughts?

You already have an MT 370Z. Why on earth would you want an AT 350Z? :icon14:

It's essentially for someone else (the 350z) and the car is super clean. maybe do a trans swap later on.

Clean HRs are getting harder and harder to find but that is overpriced for an auto. The 5 speed the 350s have is pretty meh.

Update: No problems with gauge since checking sensor, replacing battery and discharging system. Never brought the car back to the dealership to replace the gauges.

ECU's are a funny bunch. Often it takes a few drives and miles while the ECU "re-learns" and resets.

I have learned to be very patient when it comes to electrical things and ECU's in cars, specially Nissans. From the early OBDI in my 1996 D21 P/U to my 06'Xterra, 13' Murano and 17' 370Z. They can be a headache, but predictable.

I drove that D21 Hardbody for 350,000KM's and 21 years the only CEL I got was for an O2 sensor. Sometimes simplicity is best policy. Never changed a light bulb on that truck!!!

When car batteries start to go south. It will do strange things to the ECU. Most ECU's will shut down at 10.5 volts to protect themselves. They don't like voltage spikes either. When starting with a bad battery. You will get low voltage followed by a voltage spike after starting. The most sensitive part of the ECU will react to the voltage spike. In OP's case. It was the oil temp gauge. Hard to figure out at times.