99 chevy (obs) 5.7
it starts off cranking like its going to fire, but then the cranking slows down for a second. while the cranking slows, the voltage drops to about 10. then it cranks normal for a couple of cycles, then gets drawn down. and repeats. it stutters while cranking. could it be a starter malfunction. when the massive draw comes on, there is not enough spark to ignite the fuel? i hooked it up to a jump starter with 200 amp capacity. even with that there was the lobe during the crank cycle. help me please.