I have what appears to be an intermitent misfire on my 98 Uk turbo.Can occur in any gear when accelerating,run it on optimax for the 3000 miles I have owned it,has scoobysport back box,magnex decat centre and ITG panel filter with no other mods.I would appreciate any suggestions as to where to start to solve the problem,the fact that the misfire isn't there all the time makes me think it could be electrical/heat related.(perhaps plug leads or coil packs when they get hot?)

 

The now legendary MAF (Air flow meter)?

 

My '98 car had a similar sort of thing, intermittant misfire. My old boy, an ex-Lancaster electrician from WW2, told me it was ignition, no doubt about it.

A Subaru dealer said it wasn't, and had 3 goes at fixing it, as it didn't show on the fault codes.
Finally they traced it to a dodgy plug lead!!
Alcazar