Not sure if others are finding this or its just a local issue to us. Myself and a workshop next door to me are seeing a number of cars that are being remapped that are having issues with the remap.

I had an Alfa in last week that had failed MOT emissions. The car was running very very rich. Plugged KTS in and read fault codes. No codes stored. Thought that's a little odd seeing how far out the tail pipe emissions are. Checked live data and could see before and after cat lambda readings showing 0.8V on both and no movement at idle and fast idle. Checked fuel trims and found both short and long term fuel trim at 0%.

Another quick chat to the customer and it was evident that the car had been remapped recently. So we advised that the car was returned to stock and we would take another look at it. The customer returned to the tuner and they agreed to put the original map back on. Unfortunately the customer returned the car to MOT for retest without us getting a chance to take another look at it. The car did fly through its emissions test though so it was correct diagnosis.

So just a thought it might be another question to ask the customer before commencing diagnostic work on the car.