Stig,
Thanking you,
1-> 1996, Nissan GA15 EFI 1.5L engine, Battery age is 1 year & 8 months. (Checked voltage, alternator etc. & all fine)
2-> This is the explanation mate. what else u want more clearly? Ya. this seems to happen if drive the car sometime, stop it, let it parked about 30 minutes or few hours. Eg. go office, park the car, try starting evening
Morning starting happens just fine almost all the time. but there were some times it was hard as the same too....