$150 "pending charge" for gas fill-up on Monday

I check my American Express on-line statement frequently, and there is a pending charge of $150 in addition to a $33 charge for the actual gas I purchased.

This is from a grocery store gas station, but I've never had anything like this before from the same station.

I've heard of debit cards being charged something in excess of the actual purchase but never a credit card.

I can't dispute the charge until it is actually posted.

ETA: That $150 "pending charge" is still on my credit card. I googled the question and found this:

Gas Stations - At the pump

When you present your Debit Card at a gas pump[I used a credit card!], the actual amount of gas you are purchasing is not available. In order for the system to provide an authorization an amount must be present. Since the amount of the purchase is not known until the gas has been pumped an amount determined by the gas station is transmitted. The amount can vary and may be as high as $100. [My pending charge is $150 - and the actual charge of $33 has already been posted!] In most cases the gas station will send an authorization for $1.00 for gas pump transactions. The estimated total could stay on the system for 1 – 3 business days until the clearing item for the amount actually charged reaches the Issuer (First Interstate Bank). You may become aware of the difference between the authorized amount and the actual amount through Telephone Banking, ATM inquiry or Internet Banking inquiry.

People, I'm getting pissed off!