Vehicle Struggles To Start When Engine Warm

[E150_Rider]

Vehicle: 2011 Toyota Auris 1.33 Dual VVTi
Mileage: 81k miles.

Hi All,

As the topic title suggests, my Auris coughs into life after struggle for a short moment upon turning the key, though only when the engine is warm after having driven the car. The interesting aspect is it will crank into life with half the effort when starting from cold despite not having driven the car for a week (only in use in the weekend for short trips).

In terms of the Battery, it's no newer than 2017 as I've not changed it under my ownership after having acquired the car in 2018. I'd be more inclined in changing the Battery (if required) compared to the starter motor as I don't think it's the latter on the basis that the starter would struggle regardless of engine temp.

Additionally, I've deduced that the previous owner has installed the wrong type of Battery, Calcium, as opposed to EFB and this may play a part of the Start/Stop no longer functioning from around mid 2019 onwards - doesn't bother me since I'm not a fan of Start/Stop.

Would be keen to gather thoughts as well as any advice on how to diagnose and / or investigate this further.

Thanks,

E150_Rider