I think my sy has underdrive pulleys, when i turn on my lights the truck almost stalls but quickly idles faster to compensate for the extra load. I am basing all this on how my 5.0 acted after installing them.......is this a indication?
Possible. Measure the diameter of the crank pulley and the alt pulley and I'll be happy to check them with my stockers. Meantime throw a volt meter on the alt and see what happens.
