Fuel Consumption Increased After Service?

[gshyoung]

I had my Lexus IS 250 serviced at Sydney City Lexus about 4 weeks ago. It was the scheduled 5 year service, and the recall on the fuel pressure sensor was also addressed at this time. I also had 4 brand new Pirelli tyres fitted (P Zero's at the front and P1's at the back).

Before I took my car in for this service, fuel consumption was averaging around 11L/100km (this is with ECT POWER switched on). I only city driving, so a lot of it is waiting in traffic, start/stopping, etc. The car is driven every day. I don't do any highway driving at all.

After the service, I noticed that fuel consumption had increased to an average of around 13-14L/100km. Driving habits are exactly the same; still city driving, and ECT Power switched on. The car drives great and feels very smooth, but I'm a little concerned with the drop in fuel economy. I have always used BP Ultimate 98RON.

I reset the trip meter every time and it's now giving me a range of around 470km on a full tank (whereas previously the range was over 500km on a full tank).

Does anyone know what could be causing this? Should I be concerned at all?

[rickylexus250]

Yes, I would take it back to Lexus for their advice, my IS250 is coming up for the same 5 year service and I would be concerned if the the fuel consumption increased from the already thirsty V6. It may have to do with the tyres (or the new fuel sensor) but only if the ratio has changed on the back from a 255/40/R18 to a 255/35/R18

That is the fuel consumption for an IS350.

[Cookster670]

Wow...I logged onto this site to post this exact same problem. Almost identical.

2010 IS250 F Sport

60 month service / approx 70K

Average fuel went from about 11 to 12 L/per100Km. Same conditions

I had fuel sensor recall done a few months back

One main difference is that I went to a Lexus "specialist" not a Lexus Dealer (half the cost).

I use shell 95ron. I used to use 98, but found no difference in economy and it's cheaper.

In terms of measuring the fuel, i use the trip computer as a guide (which is not accurate), but I measure it off an app where I log the km's, litres in and price. I always fill up to full, so i know my numbers are accurate.

I am only on my 2nd tank of fuel since service, so it could be too early to tell (ie maybe they put an additive in which gave me less economy on the first tank). I have only just started on my 2nd tank but the consumption at this early stage looks higher than normal

[gshyoung]

Hi mate,

I haven't really gotten to the bottom of the root cause of my higher fuel consumption issue. Since my opening post, my fuel consumption has reduced a little to around 12L/100km, which is a fair bit better than my reported 13.5/14L / 100km.

What have I done differently? I increased my tyre pressure on all fours, as well as replaced the car battery which literally just died.

I'm now running 38PSI at the front and 40PSI at the rear (no idea what PSI they were before, but the ride is now more to my liking). I like how the ride feels now, it's stiffer compared to before, and I get marginally better fuel economy too.

In any case, my fuel economy is consistent with others who do 100% city driving, so I'm no longer that concerned.

Keep us posted on how you go.

Cheers

[Cookster670]

thanks for your response. I was thinking that maybe the engine computer gets reset during service and it takes a few tanks to "tune" itself. I'll check my typre pressue and see how I go also.