Focus ST170 Misfire

[Andy Mack]

Hello,

My Focus st170 has started misfiring at low revs, mostly on a neutral throttle. Ive done a bit of research and it seems on the new ST's the MAF sees to fail a lot. Is there anyway to check if it is the MAF? ive disconnected it and driven about to see if it is. It seems to be better with it disconnected but its still a little jumpy (i dunno if thats cause its disconnected). a new maf costs £107+vat from ford so wanted to know how to test it first before spending the money.

Also if anyone has any other ideas what it might be let me know.

Thanks

Andy

[Justin S]

HT leads are problems on the Black Top Zetecs,so would check that and change the plugs, because damp gets in and arcs down the plug to earth itself.Use some silicon grease on the leads before putting them on the plugs to seal it too.