Update: Finally was able to speak to an assistant store manager(manager was on vacation) and the explanation given was that a $150 hold is placed against the credit card for "certain" transactions of varying amounts. No specific reason could be given. It could be placed on purchases as little as $10. I suspect an out of state card may be the trigger in this case. It is also at the discretion of the store manager/owner which explains why it has not happened at any other PFJ I have used.
The lesson here is to read the fine print disclaimer on the face of the fuel pump which many of us ignore. Lesson learned. Pilot/Flying J fuel cards seem to be the answer for us nomads who travel this country in RVs.