temp sensor

[bmx22]

i have been runing the same set up for about 1-1/2 years, daily drive 50 miles and at least 20 drift events and countless street sestions with no movement on my stock temp gauge, but lately if i pound it the needle go's up one line above normal and it will drop back to normal if i keep driving normal and not pounding it..could the temp sensor be craping out ..........

set up if it helps
Howie (sumit racing) aluminun radiator fater than koyo
14 inch fal single electric fan
nizmo ther.
50/50 coolant and royal purple ice additive
front mount-but always had fron mount and no problems for 1-1/2 years