1995 Peugeot 306 XTdt

Maintenance | Q&A | Fuel Consumption | Forum

The graph below covers a period from March 1998, soon after I bought the car, up until June 2004 when I sold it.

Fuel consumption was measured by recording the date, quantity of fuel added and the car's odometer reading at each visit to the filling station (when the fuel tank was filled). This information is then entered into a spreadsheet periodically to produce the graph. Because of the inaccuracies of the method, instantaneous fuel consumption calculations are unreliable and so an average of the last 5 calculations are plotted.

Click one of the following links to download samples of either the Lotus Smartsuite 97 1-2-3 (44k) or Microsoft Excel (61k) version of the spreadsheet I used.

Jun 2004 179,000 miles	Pretty much right back where MPG has been in June for the past 2 years!
Mar 2004 173,000 miles	Fuel consumption levels have returned to normal levels for this time of the year. It was unusual seeing the best fuel consumption of last year in December.
Jan 2004 167,000 miles	The car's useage has changed again. Doing about 500 miles/week, 320 of those being motorway cruise at around 70mph. Rest are relatively short city journeys. Still at the efficient end of the scale though. Very impressive for this time of year.
Sep 2003 163,500 miles	The car's not being used much at the moment and when it is, these are predominantly long runs at around 60mph. Very easy on the car, and even though we're into autumn, we're still achieving nearly maximum MPGs.
May 2003 160,000 miles	It's reassuring to see the MPG quickly breaking the 52 mpg level this year. There's a few more relatively short journeys (<10miles) and the car is still plagued with the occasional blue puff of smoke after a period of idling (see here for more details). However, I am still doing a few longer trips and these are usually 60mph cruises and so this no doubt explains the good fuel consumption.
Jan 2003 154,000 miles	A mild winter so far and when I know it's going to freeze the car goes in the garage. Seems to have had a positive effect on the winter MPG.
Sep 2002 147,000 miles	Best summer yet! Perhaps not surprising. A house move means my driving pattern has changed. Pretty much all on either motorways or fast A roads between 55 and 70mph. Pretty much ideal conditions for the 1.9TD engine.
Apr 2002 140,000 miles	Things look back to normal thank goodness! I may have been too quick to think something might have been wrong back in February. We are only talking about a 2 mpg difference from last year and the readings are very similar to the same period 2 years ago. Anyway - things are back to normal now and we are heading back up to 50mpg territory.
Feb 2002 136,000 miles	Oh 'ek! What's happened? At first glance it looks like the bottom has fallen out of my 306's mpg! You can see the big fall from December upto present. I haven't noticed any change what-so-ever with performance so that's good and my driving style has not changed either. I think things just look bad compared to last winter which was very mild. Not that it's been too bad this winter but you can see that the MPG did reach a similar level back in April 2000. So I'm happy to wait and hope to see things sort themselves out. One final thing worth mentioning. The car had it's annual service in January (no problems there) but I usually accompany oil changes with a shot of injector cleaner in the fuel but this time I haven't gotten around to it. I'll probably do that tomorrow, not because I don't think my MPG will improve without it but just because it's a habit. Fingers crossed.
Oct 2001 130,000 miles	Fuel consumption this year appears to have been a little more steady than last year. The engine shows no signs of wear. Fuel consumption should begin to increase as winter approaches. Looking back over the past 3 years the last 2 have definately been the best. What happened? Could it be me becoming an advanced driver early 1999?
Jul 2001 125,000 miles	Well - this is almost becoming a bit boring. No real surprises with fuel consumption. Ignoring last years blip around this time, fuel consumption is pretty much where I'd expect it to be and is similar to 2 years ago. It's quite easy to make a prediction of future fuel consumption. I should be in for at least another 2 months of around 51mpg motoring - yippee!!
Apr 2001 119,000 miles	Again, current fuel consumption appears to match almost exactly the figure from 12 months ago. Average fuel consumption over winter appears to have done a little better than last year. Since I don't think the weather has been any less servere, I believe the better fuel consumption might have been due to a reduced number of cold engine start-ups since I now do not always have to commute to work.
Nov 2000 113,000 miles	The predicted increase in fuel consumption as winter approached seems to have started during November. The trend of the graph is down and I expect this to continue in the same manner until next Spring. Looking back a few months we can see that the car's best MPG figure this year almost exactly matches last years figures. So after another 22k miles, this 5 year old engine engine shows no signs of reduced performance.
Aug 2000 107,000 miles	The gradual decrease in fuel consumption as we've moved from Winter to Summer has been interrupted by an uncharacteristic dip at around the 104,000 mile mark. This may be due to a slight change in the use of the car during June/July - more full loads and perhaps more frequent, shorter trips. The car's usuage is now back to normal so I expect the fuel consumption to level out and be steady during August before starting to dip in September.
May 2000 99,000 miles	I guess we didn't have a particularly bad winter and so in March, my MPG started to improve. Looking back a year we see that we are pretty much following last year's trend. The car is running well - if anything I forgot to add diesel injector cleaner when the car had its last service and also its air filter is due for renewal. It's due for another service anytime now so I'll do them soon. Hopefully the trend will continue upto the 50/51mpg mark in the summer.
Dec 1999 92,000 miles	This prediction business is easy! Maximum fuel economy was maintained until September/October at which point it began to drop as winter approached. Only point to note is that economy is still bettering last years figures by about 2mpg. There's certainly no sign of engine wear as this engine approaches it's 100,000mile birthday! Another famous prediction? Hopefully fuel consumption won't decrease below the current level of 47/48mpg. It should remain level until March.
Jul 1999 85,000 miles	My god! That was a good prediction wasn't it? Here we are at the end of July with an average MPG of about 51mpg. The trend since Spring has been almost a perfectly straight line. I can't imagine temperatures getting much hotter than they are right now (daily averaging around 20C) and so I expect the graph to level out around this point - 51mpg. August should be warm and September things should start cooling so I expect to see mpg start falling then. We'll see won't we? ;-)
May 1999 82,000 miles	Rather than remaining steady as I predicted in March my MPG has continued to improve. I'm now just passing the 49mpg mark. This is 2mpg more than I was achieving last year at this time. My prediction for the next couple of months is a continued improvement because of increasing ambient temperatures. By July I expect to be matching last years best mpg of about 50.5.
Mar 1999 76,000 miles	At 72,000 miles, fuel consumption is at its poorest. I would have expected the car's fuel consumption to remain steady at this point until ambient temperatures began to increase in the Spring. However, two things happened at this point which may explain the slightly better fuel consumption after this point. Firstly, the car had it's 72,000 mile service which for this car is it's biggest and included having it's timing belt change. Secondly I began my Institute of Advanced Motoring course. Since the car's performance didn't appear to change after it's service, I do not believe much of the better fuel consumption can be attributed to this. However, learning to become an advanced driver did cause me to start sticking to speed limits and paying more attention to use of the accelerator and brakes. This I think does explain the significant improvement in fuel consumption for this time of year.
Sep 1998 65,000 miles	With the onset of Autumn after 64,000 miles the trend of the graph is downwards. This is normal since ambient temperatures are falling and petrol stations begin selling diesel with winter additives which has a detrimental effect on fuel consumption.
Jul 1998 59,000 miles	With the onset of Summer and hence the engine running more efficiently and the removal of winter fuel additives, the general trend of the graph is upwards. The dip at around 59,000 miles is probably me discovering that the car had a turbo! The car was used, pretty much, every day. During weekdays this would involve the daily commute to work and back consisting of approximately 85% motorway driving. At weekends there would be a greater proportion of A-road and B-road driving. On average I would cover about 450 miles per week. The car covers approximately 20,000 miles per year. It is serviced according to the manufacturer's schedule which is every 6000 miles. I let a garage perform an annual major service whilst I perform the 6,000 mile services myself.