just started today, when the engine is warm at tickover the revs drop to nearly stalling point then suddenly rev up back to about 1100, then drop back to stalling again, and so on, its as if I am gently pushing the throttle. The car starts and runs perfectly, its a MY00Turbo by the way, any advice appreciated!

 

Have you had the battery disconnected recently? or performed an ECU re-set.
If so looks like it could be a MAF problem

 

sounds like it it could be you idel control valve try cleaning it out and see if that makes a difference

 

agree sounds like maf

 

I just read another post on here by somone with the same problems, and yes, I fitted a new battery yesterday! Can somone explain why doing that buggers the MAF sensor? And exactly where is it situated, Im guessing in the airbox or nearby, can I change it myself?

Many thanks to all you knowledgeable people!

 

Ecu learns to run with a dodgey Maf.
Change the battery and the ecu resets and car feels like a bag of spanners.
About £80 to replace - 2min job. On the pipe next to the air box, unplug and undo 2 torx screws.

 

defiantly the maf,i had the same problem on my classic recently and one of the soldered connecters on the maf had a break,resoldered now running as new.it did take a while to be spotted as it was on the rollers for almost an hour.but eventually found.

 

Drive it off boost until you replace it. It is situated in the large pipe that comes off the air intake box. You will need a torx set to undo the MAF.
If you drive it hard you will be looking for something more than a £70.00 MAF,
The engine has a tendency to run lean in this state and can cause detonation, which is a big NO NO on a turbo-powered car.

 

Once again, a big thanks to all for your help!