Have replaced the plugs and leads on my Escort GTI but it still has a slight missfire when at idle and the car seems to quiver yet when I drive off it dissapears? Also it tends to hunt quite a bit and also sometimes when I pull up to traffic lights or a junction the idle sticks at 1500 and dosnt drop for about 30 secs then when I drive it again it feels like its running away with me cos its idling high.. grrrr any ideas cos its driving me up the wall

 

High idle can be caused by an air leak. Check all hoses for cracks and leaks around the inlet manifold.

 

same prob on my focus a hose had a hole in it drawing in extra air causing lumpy idle/holding the rev's up and or stalling
or you have a gasket gone on your inlet manifold

 

Funny you should say that, there is a hissing noise coming from the engine somewhere! I will see what I can find

Thanks

 

Also check the PCV valve, if these stick they let air in and cause what you have including the misfire, as if stuck open at idle(should be shut) they weaken the mixture, to a point where it can be too weak to ignite correctly, no correction is made for this as it is after the air flow metre.
tabetha

 

a comon problem is the rubber breather pipe splitting underneeth the coilpack. it goes to the inlet manifold. dous the hissing sound underneeth the coil pack? best to remove coilpack to repair

 

Well I cant quite decide where its coming from, sometimes it sounds like its coming from down the back near the manifold and then other times it sounds like its coming from near the air filter lol

 

hi im having the same problem with my s2 turbz can any one help