I have a lowly but lovely 1.6 LX, so I don't have a fancy internal computer thingy to tell me the temperature, etc. You will have discovered elsewhere in the forum what mpg you should expect with a 1.8 - probably around about 26-30 around town, depending on how you drive. Perrys won't be able to help you with your PCM or ERG updates, so you need to find a ford franchise for that. They should find something missing or not updated by the sound of it. I recently had this done and my mpg increased markedly. It took an hour and cost me £50. See my post in the 'old' ford focus cmax forum under 'MPG tag' page 3. My 1.6 was spinning at well over 4000 rpm at 80mph, and now does 3750 rpm at 80.
I also drove SAABs before the Cmax. Mine were old 900s. It is a very different drive, and less torquey, so expect more revs from the Cmax. I think the 1.8 should be spinning at about 3500 at 80 mph. Let us know how you get on.
Edited by: romseyraver