I kind of had the same problem with my 97 4.6. Long story short, I replaced the major grounds and also the positives. The one that made the biggest impact was the one going to the starter. That 01 or 02 sized wire was all corroded inside the connector where you could not see. I cut the connector off peeled back an inch of insulation, and everything started to work all at once. The beeping went away, the pinging and loss of power going uphill, all went away. The rover really needs a good electrical to keep it running well. Check your connections!
JR
