Hi Bazile, are the tyres the Original Pirellis? they should be at 28>>30PSI, 20mph! there is something drastically wrong here, yes the ECU controls the fuel + others within the car, do you do very short trip? is there a smell of fuel anywhere around the car? do you use the A/C often, although the A/C increases fuel, it will not use to that extent, how much fuel do you put into the car? as £20 gives you hardly anything now in comparison with years ago, do you get into top gear as soon as you can? when I had a manual car, it was if conditions allowed, Ist 3rd>>5th, missing out the others. Do you leave the car running to warm up? I have a feeling the ECU is at fault with this car after what you have said, to exchage this is a costly job, can you find out from the V5 who the last owner was? if so ask them what was their reason to get rid, if the answer was, what I think! get back onto the garage that sold you the car & ask them to sort it. this interest's me.