Icsea Posted October 31, 2018 Share Posted October 31, 2018 (edited) I've owned my car now since July this year and never thought about my fuel consumption being 3L, but I seem to only be getting 250~ miles before my light comes on which works out at about 16mpg, and with some people saying they are getting 25-30. Unless I worked it out wrong (Jspec TT Auto) I have tried search but no luck, could someone point me to a list of things to check/change to try and improve it. Edited October 31, 2018 by Icsea (see edit history) Quote Link to comment Share on other sites More sharing options...
Dnk Posted October 31, 2018 Share Posted October 31, 2018 (edited) First thing i'd do unless you've done it, set your tyre pressures, then i'd jack the car up and check each wheel freely rotates, press the brake peddle and check again, seizing calipers is common unless they've been fully serviced, especially the sliding carrier smaller calipers. Change the 02 sensor What kind of driving are you doing ? Edited October 31, 2018 by Dnk (see edit history) Quote Link to comment Share on other sites More sharing options...
Icsea Posted October 31, 2018 Author Share Posted October 31, 2018 Sorry I forgot to say its got UK spec brakes on it if that makes a difference. Just a 26 mile round trip to work no A roads so its just usually a 40-50mph cruise Quote Link to comment Share on other sites More sharing options...
The Raven Posted October 31, 2018 Share Posted October 31, 2018 A non functioning o2 sensor would be my guess Quote Link to comment Share on other sites More sharing options...
Dnk Posted October 31, 2018 Share Posted October 31, 2018 Sorry I forgot to say its got UK spec brakes on it if that makes a difference. Just a 26 mile round trip to work no A roads so its just usually a 40-50mph cruise They still seize up and can screw your fuel economy, i had a rear partially seize and couldn't tell under normal driving, take the car for a drive use the brakes and when you park up use the back of your hand near the caliper and see if any feel much hotter than the others, obviously DONT TOUCH - - - Updated - - - A non functioning o2 sensor would be my guess Was just adding this and well worth fitting a new one Quote Link to comment Share on other sites More sharing options...
Icsea Posted October 31, 2018 Author Share Posted October 31, 2018 Thanks for the advice guys, one more thing how much should I be paying for a new sensor and I read up TT has 1 and NA has 2? Quote Link to comment Share on other sites More sharing options...
Dnk Posted October 31, 2018 Share Posted October 31, 2018 £47 on tcb parts, have a shop around, dont buy unknown ebay stuff Quote Link to comment Share on other sites More sharing options...
rider Posted October 31, 2018 Share Posted October 31, 2018 I've never managed to squeeze more than 55l in my tank so I think there has to be quite a bit left when the yellow light comes on. You are probably nearer to 20mpg which isn't out of the ordinary if you are doing city commuter drives or short journeys. The easiest way to improve fuel economy is go for skinnier tyres at the right pressure and use a thinner engine oil. Also checking you have no brake binding. Quote Link to comment Share on other sites More sharing options...
Dnk Posted October 31, 2018 Share Posted October 31, 2018 I wouldn't be messing around fitting skinnier tyres, my car on 255 fronts & 295 rears would do 25 + mpg no problem To check your mpg brim the tank, set the trip, do say 150 miles, re brim the tank, make a note of the litres used do the maths 4.54L to the gallon Quote Link to comment Share on other sites More sharing options...
stevie_b Posted October 31, 2018 Share Posted October 31, 2018 Thanks for the advice guys, one more thing how much should I be paying for a new sensor and I read up TT has 1 and NA has 2? Yes, UK and NA have 2 O2 sensors. JSpec TT has one. Quote Link to comment Share on other sites More sharing options...
nigelboyne Posted November 1, 2018 Share Posted November 1, 2018 02 sensors need replaced imo I found were main decrease in mpg, you should be seeing at least 25mpg with that time driving cruising at 50/60mph. Quote Link to comment Share on other sites More sharing options...
Icsea Posted November 1, 2018 Author Share Posted November 1, 2018 So my light came on today at 266 miles I'm gonna put a new o2 sensor in tomorrow and see how it goes. Quote Link to comment Share on other sites More sharing options...
herbiemercman Posted November 29, 2018 Share Posted November 29, 2018 Hi Icsea, I have owned my NA manual mk4 from new in 1995 and i was getting 20 mpg, almost did not matter how i drove it. Two years back with 42,000 miles on the clock i had a top drawer NAT conversion carried out, the car has awesome performance, and the current current mpg is 17. It never changes much, but there again the really fast runs are few and far between nowadays with traffic congestion and the proliferation of speed cameras. I do not think these cars were ever intended for MPG watchers, all be it i used to measure it, now i just enjoy it and hope i keep my licence clean, that is where the real expence can come in. Herbie. Quote Link to comment Share on other sites More sharing options...
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