Nissan QashQai Forums

Hi all
A 1000miles with my petrol car so far, with no issues what so ever. Engine is running fine and I’ve got plenty of power.
What is bugging me is...
I just did 344miles where 95% motorway with average 70mph speed and I refueled up to the top 50l ( full tank to full tank) which is 28mpg. The board computer shows 35mpg average for that distance. On the motorway my board computer shows 35mpg all the time when I travel with 70mph. Only once I managed to get 40mpg on the board computer when traveling with 50mph on the motorway.
I know I have to change front tyres as one is more worn than the other( previous owner fit different tyres, but looks the same regarding grooves) and I have spark plugs to replace ( 5 years old car, but only 35k miles on the clock), however I’m not sure that tyres and spark plugs will improve fuel consumption...
What’s your opinion?
Should I change tyres and spark plugs and check again or go for diagnostic?
I don’t have any warning lights showing and my service history show O2 sensor replaced on 20k miles 2 years ago ( don’t know which sensor, but can ask)
Hmm.....

spark plugs and tyres won`t change the mpg much best speed is around 55mph to get good mpg, and if your car is petrol then 35-40mpg is about right

Sorry if I was unclear.
I have 28mpg consumption 95% motorway miles checked with full to full tank

It could be down to your driving style, we just purchased a 67 plate 1.6 dig-t n-connecta qashqai and I regularly get 41mpg on a 7 mile drive to work on A roads and recently on my first ‘out of lockdown’ drive down the M74 and cross country to the Solway Firth I got over 50mpg.