Q&A

serpentine belt broke so I replaced it and the altenator had to be replaced also, now the speedometer either reads zero is is erratic and engine acts like it wants to die at around 25-30mph even though my foot is all the way to the floor it doesnt come back to life until it slows down to around 20-25mph and it keeps repeating this.
No evidence of coil or ignition module problems, new cap and rotor and wires and plugs. Does not appear that serpentine caused any other damage to wiring harness or sensors when it broke. What could be causing this?