eletrical problems

[tbaker]

I have a 97 7.3l that has an electrical problem. I have checked the glow plug relay and it's working good so I put a test light on it and when i start the truck the light stays on for the proper time but then as the relay starts to cycle on and off the battery gauge starts to surge to the high side when the relay turns off. At the same time the engine also surges with it. This also seems to be a drain on the batteries. The batteries are new along with the alternator. This is only on start up when it does this. I have checked the wire harness and all the glow plugs are new. the truck has some mods. It has been chiped, k&n filter,4" exhaust

[Texas_Outlaw]

Mine does the same when its very cold outside. I havent had any troubles from it. My batteries are 1 1/2 years old and still going strong.