Missfire At Idle

[L600MAT]

I have a 02 Focus 1.6 Zetec The car has a little trouble starting but always gets there in the end when its sat at idle the engine sound like its making a poping noise and wobbles I have had to people look and it and both said it sounds like its the inlet manifold gasket would this cause this?

I have replaced the breather pipe behind the inlet manifold already along with the spark plugs when I took the 4th plug out it was black and oily would the inlet gasket leaking cause this?

Thanks in advance.

[artscot79]

possibly the gasket as said anyone on here thats had the mk1 with a misfire will tell you you can replace anything from the gasket pcv valve coil pack spark plugs and leads even then it can be a fault in the ecu

[Stoney871]

Give the plug a good wire brushing and get a can of damp start spray.

While the engine is idling, spray it around the manifold gasket.

If the engine picks up and runs smoother as you spray then it's definitely the gasket.

A dirty plug like that does say inlet leak to me.

The cylinder is running too lean due to excess air getting into it and diluting the mix.