sticky gauges

[elk_hunter]

Hi all,

 

for the past few months from time to time my speedo and tach guages has been sticking. I'll be at a stop light and the mph is saying 30, tach at 2,000 etc. or be driving on the highway, and go to pass someone and the speedo wont move but i'm going faster. Then all of a sudden will work fine for a few days, then back to to sticking?

 

I have never had the cluster off, or did anything around that cluster. IS there something in the engin area i might want to check out/clean?

 

Thanks