Drivers were hit by an 8p per litre surge in the price of diesel last month, new figures show.
The RAC said the average price of the fuel at UK forecourts rose from 154.8p at the start of September to 163.1p by the end of the month.
It was the fifth largest monthly rise since 2000.
Petrol prices rose by nearly 5p per litre from 152.5p to 157.0p
The RAC attributed the price rises to oil producer group OPEC+ restricting global supply, combined with a fall in the value of sterling compared with the US dollar, which is used for fuel trading.
RAC fuel spokesman Simon Williams said: “Drivers are sadly really starting to suffer again at the pumps. There’s little respite whichever fuel drivers use.
“Our analysis of RAC Fuel Watch wholesale and retail data shows that petrol is currently overpriced by around 7p a litre, although the price of diesel is likely to go up further still in the coming weeks.
“It’s worrying that retailer margin across the UK is higher for petrol than it should be considering the big four supermarkets were told off by the Competition and Markets Authority for overcharging drivers by £900 million in 2022.
“While many have voluntarily started to publish their prices ahead of being mandated to in law, we still have a situation where wholesale price changes aren’t being fairly reflected on the forecourt.”