Mira ES low average issue

[abbaskumail70]

I have Mira ES 2014. It was giving average of 14.5 maximum in the city and its pick was not good. So I changed the engine oil and got the car tuned by a local mechanic. He removed the battery terminal first before opening the engine.
He cleaned the throttle body, spark plugs and catalytic converter.
Now after the tuning the pick got quite better but the car's engine noise is louder than before. Don't know if it is High RPM issue because the mechanics didn't had a scanner.
Moreover, when speed reaches below the 10km/hr car gives a jerk as if something is blocking it from moving.
It is giving average of 11.4 km/l now. Kindly suggest what to do.

[xhaikh1]

does any check engine light is on or not?

check the air filter area and throttle body area that is there any wire unplugged available or not if it there then plug that wire and remove the negative terminal for ten minutes then put that terminal then check that.

[abbaskumail70]

Engine check light is off

[xhaikh1]

which brand of oil you are using now,
your IAVC is stucking somehow,
if you dont want to do anything by mechanic then usee first the mix of hi-octane your injectors are dirty or throwing wrong pressure.
did he wahsed the throttle body. if he does then there was the carbon on butterfly of throttle body which is now cleaned because of these its taking more air than actual.

[abbaskumail70]

Ok I will do the high octane thing.
He cleaned the throttle body.

[abbaskumail70]

Helix 5w30

[xhaikh1]

then there will be minor adjustment in the throttle body by losing the adjustment screwer to adjust the idle