Are you sure the OBD reader works? Does the car go into limp mode?
how long does the CEL light stay lit? Normally the errors are logged in the ECU for a while and then once they are repeated or constant then the light goes on and the car drops into limp home mode, and will not come out of limp home until the errors are reset via ODB. So if the light goes out on its own and the reader does not see it, then its an intermittent fault that is getting cleared. Can you hook up a software based ODB package to a laptop and log it while driving see if you can pick up the problem?
I'd give it an "Italian Tune" and Battery reset first then see how it is. Also do pedal reset too.
However i would say if the light is on all the time there is a code in the ECU which will tell you whats upsetting it, guessing with these cars can be a very expensive business!!! i would agree that if it does not go into limp home mode then its less likely to be TB or pedal sensor, so lambda sensors maybe or knock sensors, these are also prone to problems and don't create limp home mode but some times off peak performance.
i have used several cheaper ODBII readers and they all worked to some extent in the 3200. i have recently got "dash command" using a WIFI ODBII adapter and its very good, as it also does a good job of live gauges and plots of sensor outputs and so can help with diagnosis.
If it's on permanently, and you can't clear it via battery reset and some spirited driving, then it looks like a trip to the Stealership or Indie is imminent.
There's a new Maser dealership on the Penarth Road - Arrow Maserati - you could give them a call for a quote. If the service staff have anyone from the old Dick Lovett Cardiff dealership on their books then I'm sure they will do their best to accommodate you for minimal cost.
Don't understand a word of that!!!
software to read the codes etc is this
https://itunes.apple.com/gb/app/dashcommand-obd-ii-gauge-dashboards/id321293183?mt=8
you have to buy it, and you will need one of these to use it
http://www.ebay.co.uk/itm/Mini-Vgat...975?pt=LH_DefaultDomain_3&hash=item2edab7337f
I found this works well using my I-phone, reads both impending codes can clear the codes and also allows custom gauges and logging plots its a good tool.