2-5/8 summt gage acts funny
 

I have installed a summit 2-5/8 temp gage a year ago and this year it is acting funny. It is a mech installed at the intake, the problem is when I start it up after setting a long time (30 days) between starts I have to wiggle the thermocouple where it is threaded in the intake then it will register at the gage. If I start it after a couple of days it works without touching it. Any guess?