28i poor fuel economy

[Mido01]

I recently bought a used 2012 BMW X1 xDrive28i as my first car with 103k miles on it. I noticed the gas mileage is very bad on my car compared to what is there online. I got 12.6 US MPG average on 112 miles mostly city driving and sometimes hard acceleration. I was thinking I will get close to the advertised 23 MPG city driving rating at least.

Today did almost fully highway driving for about 18 miles, averaged 19.3 mpg with cruise control on which is no way near the advertised 32 highway mpg.

I am suspecting spark plugs because I think I got a misfire when hard accelerating when the car was cold a couple of days ago that triggered the check engine light and limp mode but then was resolved after an engine restart.

Another thing is that the engine starts slowly as in it cranks but takes like 2 seconds to actually start. The battery was changed 2 years ago but I will test its voltage so that I can eliminate it from the equation.

Other than spark plugs, there is the O2 sensor, ignition coils and clogged injectors that could potentially be faulty.

I am getting an appointment to have the car checked and will update. Also share your experience if you went through something similar before.