When I drive at speeds above 50mph my charging needle goes to 18v and most of the time the od reads no bus. Any idea where to start. I have not had any battery problems.

 

I think either your battery is cooked or your alternator is bad. take your alternator to a NAPA dealor or anywhere else and get it tested. they can probably do a draw test and check your battery as well.

 

Also, as soon as I slow down or come to a stop, everthing goes back to normal.

 

i'm going to guess the internal regulator in the PCM is bad. it should be limiting voltage to about 14-15 volts. there's a few good threads about "no bus" you can search and find, which are usually either a bad ground, a bad sensor, or the pcm is bad.

i'm thinking you have a bad pcm, and the no bus isn't worth chasing until you solve the overcharging. it could also be caused by the overcharging.

 

......

 

Mine jumped to 18v when I was accelerating one time and I immediately stopped and shut it down. When I got to poking around the engine I noticed that my negative battery cable was loose and it was burned on the post a little bit from arcing between the loose cable and the post.
Putting a spacer between the cable and the post to make it have a tight connection made it fine until I got a new end on it.

 

I not exactly sure why, but the problem is fixed. I just put a new universal joint on the drive axle, the old one was copletely gone. In fact it just fell apart after I took the drive shaft off. I driven it about 250 miles going up to 70 mph and no problem.