Hi
When I tested the replacement ECU for MMC. I had the limp home mode several times and also the start on one bank of cylinders. The start on one bank of 3 is due to a Cam Sensor not working properly and/or a High Voltage spike from the HT Coil that is nearest the Cam Sensor that is causing the HT noise to mask the sensor current, the result is that the ECU cannot accurately read the electrical signal from the cam sensor due to HT noise and therefore cannot set up the Cam advance correctly on start up. So one bank only fire and then it dies.
The noise was induced due to the path to the loom for the replacement ECU from MBE supplied by MMC. So you may have a noisy or failing HT Coil on one of the spark plugs.
The other issue you describe, going into limp home mode maybe due to the above but it could also be due to the accelerator fly by wire. It sends a voltage to the ECU that at no throttle is 0.5volts and fully open 4.5volts. This is supposed to be a linear increase, obviously it will be stepped and not perfect, the ECU has a + and - range for the linear graph as no electrical circuit is perfect. Now as the MBE supplied ECU was programable they could adjust for this variance, it took some time to realise that they had transposed one of the figures and was too small causing the limp home mode at 5000rpm to sometime occur, so a particular point of the Accelerator pedal. So if your car is a standard out of the box 3.7 roadster it may have 2 issues the first and the second fluctuating voltage going out of the range of parameters entered in the Ford ECU programming.
As for the dealer saying you need a replacement upgrade ECU, I do not agree, the car was working fine until now, it would have had the rev hang issue documented by me and many others, which can only be resolved by the ECU that the dealer is referring to. The current issues I would suggest are due to something changing on your car, be it cam sensor, HT Coil pack causing noise, and probably fly by wire throttle issues.
I hope this makes some sense to you. You are welcome to PM me if you wish to discuss further.
