Help needed - 2011 Jimny violent knocking, shaking, engine cuts out and fuel

Hello all! I bought my beloved 2011 Jimny back in summer 2021. And it has been perfectly fine until end of last year and since, it keeps breaking down and then coming back to life by the time rescue comes. But the same issue keeps happening. Vary mechanics have looked it over for hours and nothing is visibly wrong, and of course it runs perfectly fine for them. No warning lights have come on at any point. So, what actually happens: I have been driving along on the straight and flat, in 2WD. The speed I’ve been driving when this happens has varied from 20-50mph. When driving up to 50 on the flat and straight, the Jimny suddenly pulls back and I can’t get above 40 and get slower and slower, while
at the same time the whole vehicle shakes violently and makes a loud knocking noise until the engine cuts out and then the inside of the vehicle fills with an over powering smell of fuel. The same thing and sequence of symptoms happen every time. I get rescued and it starts fine and runs fine after! But I only get a few days out of it and it happens again and again. It spent a whole week in the garage for them to
look over and take it on runs and nothing came up. They’ve no clue what is wrong as they say there is nothing wrong. But clearly there is. 

I’ve read the thread on the death wobble, I’m not sure it’s that as the engine cuts out, I don’t control the slowing down of the vehicle, it slows down, despite my foot on the floor until the engine just cuts out after the violent knocking and shaking, and then the fuel fumes almost knocking me out. 

does anyone have any idea what it could be for me to take back to garage (if I make it!) and ask them to check? 

all help will be gratefully appreciated!

thank you
Kelly 

It sounds as if you have a misfire on more than one cylinder.  Does it do it only when warmed up?  There are a couple of sensors which are known to give trouble, or it could be one of the two coil packs gone bad.

Firstly where are you located 
Could be crank sensor
But not sure about fuel smell 

Thank you for the quick reply! Misfiring was ruled out, coils were checked and said to be in good condition. It seems to be a total mystery.

Thank you for replying so quickly! I am located in Angus, Scotland. Crank sensor hasn’t been mentioned so far, so will note that down and ask the garage to check. However when they hooked it up to diagnostics (as with each time I broke down) nothing comes up on the computer.

The crank sensor is the usual culprit for stopping when hot.
The signal disappears and the ECU thinks the engine has stopped, so no error codes are set.
Usually pouring cold water over the sensor will get it to start again, or wait until it cools down.

However, it shouldn't smell of fuel or make a knocking noise, as it stops injecting fuel and the sparks- but there could be a fuel leak as well as this fault, and the knocking could be because an engine or gearbox mount is gone.

When the crank sensor stops working the rev counter drops to zero, signifying that it thinks the engine isn't turning at all.