Voltage drop when slowing down

[ATMINF]

Like the title says, whenever I get off the gas and slow down like approaching a stop sign, my voltage drops and everything in the truck slows down, and the lights dim. Then after a couple seconds (1-3) the volts shoot back up to normal. The truck is a 2006, 3/4 ton with a 6.0l gas motor. I had asked about it before, and the tread said to disconnect a wire, but it must be for the newer trucks as the wiring was different than on my truck. Is it possible the alternator is going bad? Thanks!

[txab]

Best to get the charging and starting system, including the battery and connections, tested