Chancellor Jeremy Hunt has been urged not to hike fuel duty in his autumn budget.
The RAC told him that increased pump prices could push inflation even higher.
Analysis by the motoring services company found there is an “extremely strong link” between the two.
The Treasury cut fuel duty by 5p per litre in March.
Average pump prices have fallen from the record highs of 192p per litre for petrol and 199p per litre for diesel in July.
However, the RAC said the average cost of a litre of petrol rose by 4p in October while diesel was up 10p.
RAC fuel spokesman Simon Williams said: “When the prices drivers pay to fill up rise, inflation seems certain to follow.
“That’s something the Chancellor must recognise as he considers what action to take today.
“Last month, the ONS stated the single main reason inflation wasn’t higher was because fuel prices had fallen through the summer.
“Unfortunately, going into the autumn, pump prices have been increasing again, which we fear will only put further upward pressure on the headline inflation rate.
“We therefore strongly urge the Prime Minister and Chancellor not to tamper with fuel duty, as doing so would force the millions of hard-working people who depend on their cars to spend even more on petrol and diesel, putting even more stress on already-squeezed household budgets.”
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