Occasional miss fire when driving?

My Wife’s Jimny has started to drop power now and again while diving. It hunts for revs for a bit and then goes fine. Best described as a bee in a bottle lol.   Sometimes at lights it hunts for revs also, but doesn’t stall! 

It’s an 09 plate on 93k, regular servicing etc. there is no engine management light on, so struggling to know where to start? 

any help?

As Lambert said remote diagnostics is difficult. It could be many things such as coils, idle control valve (ICV), crank / cam sensor or even battery voltage.
Your description of the fault and subject are potentially different problems. If you can confirm a miss fire or cut out of the engine then it's likely electrical. A drop in power (but no miss fire) could be a blocked exhaust system or intake, hunting could be the ICV. 
So be as accurate as you can with the description and when it happens (engine hot / cold etc). 
We will all do our best to guide you.
 

Thanks for the reply guys.

It’s while hot it happens. The car doesn’t cut out, but drops power for a short period and then kicks back in. At lights sometimes the revs will fluctuate like it wants to stall, but doesn’t.

When it happens while driving, it’s best described as a bee being stuck in a bottle lol.

I was considering plugs and leads, but I thought if it was that it may do it all the time. I ideally don’t want to chuck money at it.

It’s had a new cat in the pat year, but the back box has maybe seen better days. We only just mot’d it, it took a bit to get it to pass the emissions.

Has this only started since the MOT? If so do you know what they did to get it through emissions, it might give us a clue? Did they add a fuel additive to get it through emissions?

The bee in a bottle sounds a bit like a misfire, does it judder a bit as well?

I had a similar problem last year with my other car after changing the CATs, loss of power after low revs and the odd misfire. I suspected O2 sensors as one showed a fault on my code reader, then went through coils, plugs, air filter, MAF, everything made a bit of an improvement. Finally I realised it only did it when the battery was getting low, charged it up and the problem went away until the battery was low and the problem came back. Now I keep the battery charged and no more problem.

The problem you have could be a number of things, I would check/charge the battery, at this time of the year with the lights, heater, demist on the battery takes a real hammering.

Plugs and leads are an easy check, check the coil packs for cracks.

I assume the air filter is clean, but what about water in the fuel, filled up anywhere unusual or only had problems since filling up?

Jimnys have two CATs, one underneath, the other in the exhaust manifold, the manifold CAT is known to disintegrate and clog the exhaust, this might cause it. It won't be your backbox, unless it is full of water and very clogged.

Hope that helps.

Robin