That`s 12.6 volts at idle.I checked resistance values between ecu plug and various sensors today.All seemed ok and within the allowable range except for the ignition module which gave a reading of 11k ohm and the resistance between the coil low tension wires was 2k ohm.I changed the ignition module over to the one which read 26k ohm and the resistance went up to over 5k ohm at the coil lt wires.But it made no difference to the flat spot.I removed the air temp sensor plug and then started it.It ran rich for a moment and the flat spot disappeared for 2 or 3 blips of the throttle and then it returned.I then replaced the air temp plug and removed the coolant temp sensor plug and tried to start it,it fired once and wouldn`t start.Again ,once it reached normal operating temp (about 10 minutes) the flat spot went away.I put a stage 1 chip in just to try and no flat spot at all from cold,sound like a fuelling issue, what do you think ?