Consumer prices increased 5.4% in June from a year earlier, the biggest monthly gain since August 2008.
Excluding food and energy, inflation increased 4.5%, the largest move since September 1991.
Used car and truck prices comprised about one-third of the total CPI increase.
Inflation surged in June at its fastest pace in nearly 13 years amid a burst in used vehicle costs and price increases in food and energy, the Labor Department reported Tuesday.
The consumer price index increased 5.4% from a year earlier, the largest jump since August 2008, just before the worst of the financial crisis. Economists surveyed by Dow Jones had been expecting a 5% gain.
Stripping out volatile food and energy prices, the core CPI rose 4.5%, the sharpest move for that measure since September 1991 and well above the estimate of 3.8%.
On a monthly basis, headline and core prices rose 0.9% against 0.5% estimates.