Got a problem at the moment where when driving the car it suddenly sounds like a tractor and the message 'Fuel Injection System' is displayed in the message read out. When you stop and turn the engine off and on again all is back to normal and the message disappears - until next time. My thinking is it could be the injector loom as mine is original as I suppose with the age of the vehicle due for renewing. Anyway I thought I would check the connectors in the ECU box on the front left hand side of the engine bay , when opened I have found a PSI Motorsport PowerLink box plugged in ! Does anyone have any idea what this does etc ? I had no idea it was there and have owned the vehicle for nearly 5 years ! Any idea if I unplug and remove it what should be plugged in etc ?

Usually these kind of tuning boxes just go between the ECU and the injectors, fuel pressure regulator or timing sensors.

Normally they have a Y cable on them. So you unplug it from the car's loom and the main ECU and remove it. Then the original connector on the loom goes back into the now vacant socket on the ECU.

If it was me i would remove it and see how the car ran without it, if the problem goes away, and the car is ok after a few miles driving, then it suggests the box is at fault.

Update - a few years ago I had an injector leaking which caused very poor - almost non existant - starting. As part of the diagnosis I fitted a new non genuine secondary fuel pump but kept the original one - fault was a leaking No1 injector which was replaced with a new one. Anyway today I have refitted the original pump and the car now goes like a scolded cat - definitely not standard 177 bhp - therefore the non original pump was not only delivering the incorrect fuel amount , it has only lasted roughly 3 years and 4k miles - next time I will definitely be buying genuine ! Still don't have any info on the tuning box though Still on original gearbox at 155k with filter and oil changes - so the didn't make them all bad