Honda Civic 98 not starting when warm.

My daughter has a 98 Honda Civic that starts fine cold but if she stops at
say a garage for fuel or goes to the shops (short stops) she has trouble
starting it up again and there is a distinct smell of fuel when this occurs
(whether at a garage or not). When it does start it can either rev low or last
night it was high (2000rpm) and then dropped and almost stalled without
her touching the accelerator. But otherwise when running and driving no
missing or drops or surging of power. Changed the fuel filter under the
bonnet twice. It's got me stumped.