Power Loss / Stalling - Help Needed

Hi all, I'm a recent owner (6 weeks in) of an 08 plate Jimny. So far really enjoying the experience and love the car.However I have a problem with the car stalling and losing power. I've done a fair bit of research on this forum and across the internet, it's sounding like a bottom/crank pulley issue. 
 The issue I have is that I've taken it to the garage, they are skeptical this is the problem and think it's more likely to be a crank sensor or MAF sensor issue. I do have a warranty from the dealer, so they'll be covering the cost, but what I don't want to do is waste time/money pursuing the wrong issue (and then possibly face problems getting the money back from the dealer - I bought the car at a distance so can't take the car back to the dealer).
 I'd really appreciate any advice from this forum's experienced owners so I can point the garage on the right direction.
I'll describe the problem below:The car itself is relatively low mileage at 41k. It's an automatic and has been serviced each year of life, so is otherwise in good condition.The problem initially occured when coming to a stop, the car stalled without making much of fuss.This then progressed to a juddering stall, with engine struggling. A tap of the throttle resolved it.Then finally the car broke down entirely when travelling up a fairly steep hill, it seemed to lose power almost as if it was in the wrong gear and needed to drop down. After a bit the car stopped altogether and I couldn't get it to start. Then about 30 mins later I managed to move the car to a safer spot.I called the AA out, luckily the engineer had some experience with Jimnys and thought it was probably the bottom pulley. However it was tricky to be sure as, after the rest, the engine was running normally again.
 Any help would be much appreciated 

It definitely won't be the crank pulley.
It could be the crank position sensor.
It could be the catalytic converter has broken down and is blocking the exhaust.
It could be a coil pack.
These are all known issues with the Jimny. MAF sensors never give any trouble.

Hi Busta, thanks for your reply. You're broadly in agreement with the mechanic, which is reassuring. Based on that, I'll probably ask the mechanic to start with the crank sensor and if that doesnt work pass on your suggestion regarding the coil pack and cat.
Thanks again!

It might be an O2 Lambda sensor, if it isn’t any of the above.

Have you got an OBD code reader or did the garage use one, that should show a sensor fault or one on the way out.

Another outside chance it might be the air filter.

Robin

Hi Robin, thanks for your reply. The garage did run a diagnostic, initially, nothing showed. However after the car stalled again they got a MAF error. The problem is the mechanic is concerned that the MAF is a symptom of a different issue (ie crank sensor) and not the actual issue, so potentially a bit misleading.
I'll pass on your lambda suggestion when the car goes back in on Monday.
Thanks again

I had something similar and thought it could be a fuel issue but it turned out to be the coil pack/leads.
If you do a search of posts on here for coil pack post etc I think you’ll find the symptoms you are experiencing similar.
bryn