Low-range misfiire

[PomBstard]

Car is a 2007 Forester with 2.5 NA engine. I've got a persistant misfire, particularly noticeable when cold, from around 1800-2500 rpm. Also more noticeable on part-throttle. Its not a full-on splutter, but more a jerkiness. I've replaced the plug leads, but problem still there - any ideas what next? Engine revs round to the cut-out no problem - smooth and sweet.

[stevieturbo]

PomBstard said:

Car is a 2007 Forester with 2.5 NA engine. I've got a persistant misfire, particularly noticeable when cold, from around 1800-2500 rpm. Also more noticeable on part-throttle. Its not a full-on splutter, but more a jerkiness. I've replaced the plug leads, but problem still there - any ideas what next? Engine revs round to the cut-out no problem - smooth and sweet.

And how many miles ? Have the plugs ever been changed ?

Whilst it's mostly turbo cars I work at, I'd have thought one of that age would have had 4 coil packs, as opposed to leads.

And is there a check engine light ? The ecu should be reporting the misfire and which cylinder it is occurring.

Could be a myriad of things really, from poor servicing, dodgy MAF, wiring gremlin etc.