I'll try not to be giving you too much of a saga while I give you the detail.
The engine started missing and running really rough when cold. It had a new petrol filter and air filter. We got four used, tested coil packs from Sunspares at Yandina, fitted them with new plugs and it went OK for a few days then back to misbehaving. Back to Sunspares for a used MAS sensor. We cleaned this with the proper spray stuff and once again, good for a few days. I then walked out of the front door just as he started it and saw and smelt that it was running really rich; much more than needed, so I thought the ecu must think it's a lot colder than it is. We got a brand new after market temp' sensor from Bursons, put it in along with new coolant and it was brilliant for about 6 weeks.
Now it's started misfiring when it's warmed up I'm thinking it could be the coil pack under the brake booster where it gets really hot. Or could there be anything else going on?
Any help is much appreciated.