Don't know about having to hold the ignition button, but the manual start is certainly kinda weird, the game is blocking certain inputs at certain times, and also stalling is really easy IMO.
This is what seems to work for me:
- Press ignition (just press, don't hold it). In cockpit view, you see the driver flick the ignition switch on.
- Clutch in.
- Hold engine start button for a short while (just pressing it doesn't work, and holding it for longer also seems to cause issues).
- The engine should start and keep running (look at rpm meter for confirmation, it can be hard to hear).
- Note that at this point, the game is blocking the throttle, even though you are in neutral and/or have clutch in. So you can't rev the engine, it won't respond to your input. This was the part that confused me a lot in the beginning, because it can seem like your engine isn't running (because it isn't responding to throttle and you can barely hear it over the other cars), but at the same time, the rpm meter shows you it *is* running.
- Once you're told to go, the game unblocks your inputs. Give it a full throttle, shift into 1st and then dump the clutch.
- The car will start to move very awkwardly while the game interferes with the clutch and throttle controls. Keep the throttle pedal floored during this part. If you try to have a more controlled and smooth (and less awkward) start, you will likely stall thanks to the game messing up with your throttle/clutch input.
- Only when the car is moving more or less smoothly, ease off the throttle and hope you don't rear-end the car in front as it randomly brake checks you.
- To make the manual start a bit more fun, shortly before going green, the game will once again mess with your throttle/clutch inputs to slow down the car almost to a stop and also almost stall the car again, so watch out.
- Once the race goes green, you now finally have full control.
