Whilst at the traffic lights the other day I noticed the engine revving intermittently like I was some kind of boy racer. Only I didn't have my foot on the accelerator! The car works perfectly until the engine is at running temp and then foes into this revving mode continuing whilst I'm trying to drive. There is much kangaroo petrol and even with the accelerator down, there are no revs unless it coincides with the intermittent revs of the ghost boy racer driver. Any clues anyone?


Tipo 1.6 ie sx

Which model? If it's a carburettor 1.6 DGT, I reckon it's most likely to be the vacuum sensor in the Digiplex electronic ignition unit, but check the vacuum pipe to it first. My theory would be that the ignition timing is varying wildly - but you could check this by hooking up a timing light.

There is also a crankshaft sensor (the other 'input' to the electronic unit) but I'd have thought that you wouldn't get the engine started if that was faulty.

If it's fuel injection - who knows - but it must be quite a 'primary' component to have that much of an influence. Are there any starting difficulties? Is the throttle plate closing fully? Is there a throttle position switch and if so, is it clicking closed?

-Alex