Hi i would appriciate any help as i have a prob with my st170 thats begining to do my nut in.
I bought the car and shortly after discovered a missfire under load ( high revs mainly ). The problem became really bad and on one occasion has cut out when driving.
I have changed the coil, plugs and ht leads (all oe equipment, but all looked new when removed so i think the problem was already there).
This has improved the problem alittle but i still have it. Mainly on a long motorway journey or when holding the revs in 4th or 5th i get it.

Thanks in advance