hi I've had my car around 5 years this has happened quite a few times over the years..i start the car gearbox fault mesg come up on dashboard..i put the gear into reverse but doesn't move I try few times put gear into neutral then reverse and car starts to move and light gearbox light goes off I have checked by the garage and they cant find the fault. Recently whilst driving speed drops and I have to accelerate to speed up very annoying especially as I set speed to 30miles. also jutters whilst on motorway I feel I have to hold steering wheel tight to keep control.
Running Rough, Starting & Power Loss
You need to get it scanned with the proper equipment and see what fault codes are showing .You should not be driving the car in that condition .If your garage cant find the faults take to someone with the correct diagnostic equipment .