Thanks for all of the feedback.
I took my spare battery (65ah) into the house along with the ic7k and connected it to a buckmaster OCF windom (80 M version)and hooked up a watts up meter inline with the battery.
I was able to transmit at full power, no cutouts, loaded voltage never dropped below 12.2V. This same battery was having the previously described issues when used in the vehicle on the Tar Heel 200 and Turbo tuner.
This appears to point to common mode current on the coax.
Next step is to try and bond the vehicle and use some ferrite chokes at the antenna side of the installation.
I am guessing that the bonding will have the greatest impact as the hitch receiver is about the lowest metallic point on the vehicle. Bonding will probably start with the easy stuff like the exhaust system to the truck frame, the bed to the frame, the cab to the frame, the hood to the frame, etc. I will probably hold off on drilling holes in painted surfaces such as doors. I am not looking for perfect but for reasonably good.
Anybody care to comment on the tests, results, and going forward direction?
Any health risks from the common mode current?
Also, I am assuming that if I am doing an LXPedition (search for Atlanta LXPeditions yahoo group) and am using an external dipole hanging from whatever is handy that I will not have the problem either.
Thanks again and 73.