Hi hopefully somebody can give me advice, whenever the car gets to operating temperature the temp gauge in the cluster will jump straight to 130 then fluctuates between 130 and 90. Have had the coolant flushed, thermostat replaced and the coolant sensor near the radiator replaced and still my cluster bounces back and forth. When my plug in a obd scanner it says the temperature is fine and steady, but the cluster says otherwise, any ideas? 

Sounds like a cluster display issue to me, if the running temps are fine as the obd would show, personally I wouldn't worry too much. It sounds like you've tried everything else.

Also, I am NOT an Audi technician or vehicle tech of any description and often wrong. Are there other temperature sensors that could be replaced as well as the one you have already done?

@Sid2020 knows his stuff, perhaps he can assist you better than I

Edited January 15, 20251 yr by RShole

There is one more sensor I believe behind the engine, but from what I've been told it doesn't send information to the cluster so it hasn't been replaced but im not a mechanic so dont quote me. I did think about the cluster itself messing up, maybe some solder has come lose over the years? But everything else on it works fine and reprogramming a second hand one to my car sounds like a headache :')

I know it's not a major issue but the cluster flashing at me to turn the engine off and check coolant is driving me crazy and don't get me started on the fans kicking in every 30 seconds, sounds like my car is about to take off 😆

A3 clusters of that era are known to fail, so don't discount a similar problem with your A4. They can be repaired by several companies for less than £300. ECU Testing have a good reputation in that respect but there are others if you care to search.

Away from work this week but check if you have a sensor on/near the thermostat housing also. quite common to have 2 different temperature sensors that are used by different systems.  A basic obd2 reader might only be able to access engine related sensors not body controller sensors. Check wiring and condition of connector pins one the sensors and if possible back probe the sensors to check resistance readings with a meter. resistance should change with coolant temperature change and be progressive. 
that’s a few basic checks worth trying before sending cluster away