Increased fuel cosumption after replacing spark plugs

[Cosmonaut21]

Last week the mechanic replaced the factory spark plugs on my car (1.2 tsi 105 ps).It only has 30.000kms or 18.600 miles but VW say they have to be replaced after six years and i have the car for 7 and a half.

From that day on the fuel consumption has increased quite a lot.
Nothing else changed.I have checked the tire pressures,i am the only driver and i've been driving on the same roads as always.
There is no lights on the dash,no eror codes appearing after scanning,nothing.
On the freeway my average has been 6-6.5lt and now i am at 7.5
In the city on my way to the University and back i could easily manage around 7 litres and now it says 8-9.

Has anyone else experienced something like that?
I am thinking that maybe i should change them again myself.

[iichel]

Did you only change spark plugs or also other things such as filters, oil?
Do you notice any stutter, misfires or loss of power?

[Cosmonaut21]

The only thing that has changed are the spark plugs.Literally the only thing.
On another forum some people suggested to check the gap and if that is ok to check if they are genuine or not.There are many fake NGK (and Denso) spark plugs out there.
I haven't noticed any missfires or stutter but i haven't really gone all the way to redline and i am kinda skeptical whether i should if there is something wrong.

[TWR]

I think your answer is in your Question, find out what plugs have been used on your car, in your Handbook & in the Specification it should tell you what plugs to use by the Manufactures.

[sirdimitris]

Για ξαναβαλε τα παλια να δεις αν φτιαξει!

[Cosmonaut21]

Which is the part number for the original spark plugs? Also are they manufactured by Bosch,NGK,someone else?

[iichel]

an original spark plug for the 1.2 TSI 8V has the part number 03F905600A and can be both from Bosch or from NGK.