Pyro is acting erratic , drops out 300 degrees then back up. sometimes falls all the way to 250. I shut the truck off when it read 250 and it went to 400. anyone have this kind of trouble, its a diprocol gauge. Also there are two 12 volt feed wires ,to it plus the lighting wires. What do they do ?? My pyro in my 96 doesn't have them. thanks, doug

 

after shutoff, it is normal for the EGT's to climb up some since the heat isn't being pushed out anymore. All the wires on the gauge except the ones in the plug are illumination, it has the normal bulb AND LED's.

 

This movement is not normal, the needle is moving around like a ball, in a pinball machine.

 

There are 4 wires in the plug, plus 2 per bulb.