Autometer Cobalt C2 gauge problem

[ZombieSoldier]

ok I have autometer Cobalt C2 electric gauges on my 1999 F250. I have 0-30PSI boost, EGT, and Trans Temp. all gauges shine the same bright blue level. My boost works great moves like it should and my truck maxes out at 24PSI. Trans temp again moves the way it should, no issue. EGT... well that's a different story. for the first 2 months worked as it should, but recently it just spikes around however it wants to. only time its steady is if i am on the highway at a steady speed for more than 20 minutes then it operates like it should. I dont even know where to start trying to figure out what is wrong. i checked to make sure the probe is in there correctly, and it is... dunno what else to look for. Please help me. next month i have a dyno day to go to, and dont want to risk grenading anything due to a gauge that isn't working properly. Only time i know the EGT's are getting to high is i get a check engine light right at 1300, and i dont like seeing that.

[jesilvas]

Check wires. Run a DIRECT 12v hot and ground to the battery to rule that out. Then check the thermocouple wiring

My Samsung SGH-I997 made me send this.

[ZombieSoldier]

only thing i saw with the thermocoupler wire was a small kink but that was always there. i will try that wiring thing.

[ZombieSoldier]

but if there was a wiring issue wouldn't the gauge light flicker as well?

[jesilvas]

Should be wires for the bulb, then separate source wires for the motor

My Samsung SGH-I997 made me send this.