Ok, thanks for the extra detailed information - a great help.

Ive just checked my 'common problems list' for the BA and I can't see anything that matches your symptoms.

When the Check Engine warning light is on or has been on then this indicates that the car's on board computer (PCM) has detected a fault. There are a multitude of sensors that input data to the PCM. At this point I'd just be throwing guesses at you as to what could be wrong. In most cases it's just a simple sensor issue, or even a wiring harness plug problem. The next step in the path for an accurate diagnosis is the car needs to be connected to a Scan Tool to look at what diagnostic trouble codes have been recorded in the car's on board system's memory during the time that the malfunction was occurring. When the ignition is switched off and back on again that resets the system and if the fault is intermittent the light will not come back on and the car will perform properly. You could go to the Ford dealer for a scan, but all good mechanical shops have up to date scan tools and will charge you modest a fee to carry out the scan. You could make some phone calls to get some prices in your local area.

Once we know what code/s are coming up then we will know where to look and what to test.

On many cars you can extract the codes manually by causing the check engine light to flash, but that's not possible with the BA models.

Let me know what you come up with and I'll be able to come up with an answer for you.

Cheers Glenn