It was the 10/73-3/74 oil embargo that established OPEC as a power in the oil markets.
The embargo was proclaimed to be in response to US support of Israel in the Yom Kipur war, although the real goal may have simply been to let the US sweat for awhile so that it would welcome renewed availability even at sharply higher prices.
Gasoline pump prices increased by 50% almost at once, and gas lines and fuel shortages were a reality in many parts of the country.
This was followed by an Iranian embargo after the fall of the Shah in the later Carter years (remember the hostage crisis?), which drove gas prices to $1.00/gallon, and they remained in that region for the ensuing decade, a relative bargain in the late 'nineties.
An important side effect was the drive to improve fuel consumption across the board.
This led to CAFE, but also resulted in some brilliant new products from GM, like the downsized '77 B and C bodies, as well as the '78 downsized A bodies.
There were also some less brilliant offerings, like the Olds diesel V-8, as well as the Chevette, the largest selling car in the US for a couple of years during this period.
Also, virtually every maker was offering diesels in a variety of models by the early 'eighties.
After '79, IIRC, if you wanted an MB W123 in the US, you wanted a diesel, since that was all MB offered in this market.
If you wanted a gas Mercedes, you had to pony up for an S class.
Mercedes also developed its own small car, the W201, which sold in pretty good volume in the US.
Interesting times!