KV6 breather? High revs

[Fille]

Yesterday after I overtook another car (full throttle, kick-down) the revs would stay on quite high. I reckon I floored the throttle for maybe 5 to 7 seconds. Afterwards the car woul still hold the throttle open maybe halfway, back at hone on "idle" the revs were about 4700...

Took the car in to garage to let the ic and snow melt off it. It smells quite a bit of petrol, which i guess is because of the open throttle but there is also a scent of oil.
I have read that these cars are prone to blocking their crankcase ventilation, especially in cold weather. So I will clean those two breather hoses under the acoustic cover ( are there more of them?) and probably also clean the throttle housing and check the throttle wires.
Any other ideas and tips?

[SD1too]

Filip,

It used to be called carburettor icing, but the physics is the same.

Simon.

[Robson Rover Repair]

1. for the past two days my revs wont stop climbing, shes idles higher on each gear than normal and some times climbs to 7,8 before i have to quickly switch off the engine, (had to do this on the motorway tonight so its very dangerous and nearly blew the engine)
its worse when i hold in the clutch as then shes shoots right up and wont stop! is this a throttle body fault? as ive recently changed to a better manifold but i used the existing throttle body, also gave it a clean?? i have a spare if its the reason?

No need mate, its your throlltle wire is sticking along with the small mechanism, and for some reason when it sticks it toghtens up fully. They stick when dirty, get the wd 40 out, and squirt over the throttle mechanism and the two white switches beside it. Will sort you out nicely.

It shoots up high as the gearbox is stoping the engine going through the roof, this happens most after icey and during icey weather, ive mine covered in petrol vaso jelly now and it never happened once over the bad weather.

Very common on the KV6 and the reason rover was going to fly by wire throttle on the revised but never sold KV6;s.