Black Smoke

[Hillie78]

Hello everyone. 
I’m after done help I have a Rav 4 03 plate. The other day it was driving fine. Then it’s starting revving black smoke out of the exhaust putting foot on gas pedal and nothing it stopped moving. I managed to pull into a road. Has anyone else experienced this problem before. The mechanics are saying it could be the clutch. 
and it could cost me £895 plus more if not the clutch. 
Any help would be greatly appreciated. Thank you. 

[Avalon]

Start with the basics, is it petrol or diesel, auto or manual? Did it start revving by itself? Could be turbo runaway. Did the EML light come on? Did the car go into limp mode? Have the codes been read and if so, what did it throw up? The clutch going wouldn’t generally result in excessive smoke coming out the back. I don’t know of any credible garage who couldn’t diagnose a clutch failure if they saw the car, so has it actually been to a garage or not?

[Hillie78]

It’s a diesel. And a Manual. Yes while I was driving it started revving by itself. No lights came uP on the dashboard. There was no warning signs at all. 
the AA towed it to the garage. They are not 100% it’s the clutch. It could be the gear box. So they say. 
It just happened all of a Sudden. 
It’s never really been powerful, on a long trip. I wouldn’t be able to start the car straight away. It would have to sit for 5 mins before I could start it again. But garage couldn’t find anything wrong with that issue. 🤷🏼‍♀️

[Bernard Foy]

1 hour ago, Hillie78 said:

It’s a diesel. And a Manual. Yes while I was driving it started revving by itself. No lights came uP on the dashboard. There was no warning signs at all. 
the AA towed it to the garage. They are not 100% it’s the clutch. It could be the gear box. So they say. 
It just happened all of a Sudden. 
It’s never really been powerful, on a long trip. I wouldn’t be able to start the car straight away. It would have to sit for 5 mins before I could start it again. But garage couldn’t find anything wrong with that issue. 🤷🏼‍♀️

Generally speaking it sounds like it’s the clutch is the problem, but as Alex says that doesn’t explain the excessive smoke from the engine. What sort of mileage has that engine done ??.