[AT] OT- voltmeter spiking Jeep Cherokee

[Mike]

Hi Guys, wondering if any of you have some suggestions for me regarding 
my daughters Jeep. The other day it simply refused to start, no spark 
nothing. Did a little research and found out that it was almost 
certainly the crankshaft position sensor. I ordered one only to find out 
that Jeep put is where no mans have would fit. So after dropping the the 
front drive shaft, and loosening the shifter linkage from the 
transmission body, I was able to get to the two bolts holding the thing 
to the bell housing. Using a 10" and (3) 3" extensions and a swivel I 
was able to get the top bolt out, without any problem. Of course the 
lower one was rusted tight; so I soaked it with Kroil for a few days and 
was finally able to get it off. Heat was out of the question due to the 
amount of grease in the area.
Now for my new problem, when I took it for a test drive it worked just 
fine, but all of a sudden my check gauges light came on and I noticed 
the voltmeter was pegged at 19. I quickly got it back home only to have 
it go back to normal. So I grabbed my multimeter and took off for 
another run, sure enough it spiked again, so I stopped with it running 
and checked the battery voltage which read 14.3 as I would expect. Any 
ideas on where to start looking for the problem? Any help would be 
appreciated.

Thanks,
Mike M