ASA. buddy i am no expert but i happen to own one for about 2 years.
jerks may be due to several reasons, mainly due to current issue what i think, but what i suggest is to replace and check your plug cables with your friend and see if it still jerks.
do not wash the engine with water
use stock plugs (normal ones like ngk, they should work fine)
milage should be aroung 13-14 km per litre, that is what i think, for engine
oil, use cng engine oil. (may be shell, i use total cng,but i aint no expert)
clutch may be loose or tight, but it should release completely, it should not
be like k clutch dba hua ha,if u get what i am saying..
check the fuses of your car, in cabin and under the hood
hope this helps, again i am no expert, just want to help
best of luck