On a twelve mile run to and from work (motorway) I achieve approx 34mpg but if I do 30miles say weekend out and about shopping (motorway again)I can return 53 !
Best yet 56 (that is between 70&80 in 6th gear ).
Rather inconsistent innit ?
Just had all four glowplugs replaced by renault as I reported bad return on fuel economy and one showed up on diagnostic as fault .
Waiting to see if its made much difference will report later on results
This is a diesel engine! Changing glowplugs is will not affect economy. The glow plugs are only used to start the engine. All diesel engines once running use the pistons to compress the atomised fuel, this creates heat and ignites the fuel.