Rough idle, might be down on power.

A bit of a preface/history. I bought our Jimny in late October form the UK and drove home to the French Alps, It is a 2002, manual, No ABS or Aircon. Its never missed a beat BUT.

When warm it almost dies at idle, stumbles and then picks up.

It's a bit gutless, yeah I know not a speed demon, but it's slower than my 1.9 VW T5 (84hp) and it should have twice the power to weight ratio, so something doesn't add up.

The brakes are not powerfull or sharp, there is no air in them and the rubber lines are in good condition.

It smells of fuel when you start it up initialy (only if you stad outside luckily)

Should I be chassing vacuum leaks? (there is a doggy looking repair on the evap line from the fuel tank)?

I am a bit lost as this is the first Petrol car I've owned since 93, always had diesels (had a 1980 Pug 305 and a 1983 Suzuki SJ410 before that).