2003 C70 Losing Power

I have a 2003 C70 convertible (auto) with around 130k on it. Running quite well other than an issue that has been present for some time. Being based in central Victoria most of my driving is open country during which it runs fine.
The issue arises when I come into a town and stop, such as at lights. When accelerating away from the lights the car will move off and then the engine response drops away and before clearing, sometimes with a surge, and driving normally.
I initially thought fuel starvation but during a service all was clear and no faults were showing. I had it checked at a transmission centre and they came up with an error code “9400 – Brake Pedal Sensor” for the engine.
Would this be the source of the issue? Looking for any advice before getting a new sensor and finding it is not the cause.
Thanks
Comments
Have you ever replaced the turbo control solenoid?
The brake pedal sensor code wont be the cause of that issue, it's usually the sensor in the brake booster and symptoms are cruise control won't work.
Thanks @timbo for the information. I have not replaced the turbo control solenoid, will look at sourcing one.
In relation to the brake sensor, I have found that the cruise control has not been functioning. Two itmes to replace for separate issues.
Thanks again.