Hi, my mate has a misfire on his rs, we have had it on diagnostics and no faults show, has been to ford and same result.
When you rev it has a sort of mettelic sound from top of engine. when you drive car it pops,bangs, backfires, just feels like you;ve swapped a couple of leads over.
It has had top end rebuilt, every sensor changed,coil pack,plugs, swapped ecu, turbo etc. now running out of ideas. mate has a complete rs for parts but just dont have a clue now?
Any ideas would be appreciated..

steve