was coming home form work today, was giving it a bit down the bypass, but as i slowed down for the roundabout, i noticed the rev counter just dropped (the engine didnt stall) then just shot back up again, with a plume of smoke out the exhaust, this is the second time it has happened in about 6 months.

Any ideas whats caused this?

 

Clearly the ignition was interrupted, hence the smoke, the fact that you were slowing down, was why you did not notice a stalled engine as cars motion was turning the engine.
tabetha

 

what breather does she run?

 

a Bailey one, breathing from kidney pot and cam cover returning to the feed below the turbo and vent to atmos

 

so first check would be plugs, leads etc?

 

in all truth if it only done it twice in 6 months its a case of needle in hay stack at the mo fella

 

Check all the earth's on the engine loom, mine used to do this once in a blue moon then started getting worse and worse.

 

My mate discovered that his rotor arm did the occassional twist as it wasn't sitting properly. I'd check the dissy area for sure. How old are the sensors?