Hi guys

When i free wheel at a high speed and gradually slow down the rev meter starts to go up and down by itself sometimes when ive nearly stopped it sometimes stalls or the battery light comes on and the car struggles to stay on any ideas ?

What model/year you got?

First of all it's illegal in the UK. Secondly, a modern engine with fuel injection uses no fuel at all when on the over-run, i.e when the car is propelling the engine, so to speak. It will use fuel when in neutral, in order to keep the engine idling. Thirdly, you are causing unnecessary (albeit very minor) wear when you go in and out of gear

all you are doing is confusing the sensors on the car and giving youreself trouble for it its a debate as to how much damage it causes other than that its stupid and dangerous especially at high speed stop free wheeeling and you wont have any issues sounds harsh but its just the truth mate

Its a mk2 59 zetec s and i dont go around with the car in neutral lol when im about to slow down and the clutch is in and my foot is on the brake the revs start to go up and down then now and again the batt light may flicker and the car nearly stalls :)

ahh now i get you when you said free wheeling i thought you were putting the car in neutral and coasting in that case it looks like a trip to the dealers it could be a loose wire or it can be the throttle position sensor a cam sensor or a speed sensor does the speedo drop to 0 when this happens it can also be a faulty battery the car will still be under warranty i assume so ide take it in and have it checked