ROBJOBY

Before asking my local Lexus agent to check my car for poor fuel consumption I emailed Lexus UK and got a fairly long and unhelpful reply, telling me much that I already knew. However a couple of points were of interest, as I cannot quote them directly I will summarise them as follows:- 1. Obviously not all cars are tested, but the chosen test car will have been carefully prepared to give as good a figure as possible. (If this is the case I would ask if my car can be carefully prepared in a similar manner). 2. To get the best economic performance you have maximise the use of the hybrid synergy drive, which means you have to feather the accelerator frequently, namely speed up then coast a while, then press the accelerator again to regain speed, then coast again. (I would ask is this really practical?) I too feel Lexus are doing themselves no favours by publishing very unrealistic figures and I still cannot understand how my RX400h consistantly returned close to the published figures over four years, whilst the 450h is way off it's published combined figures in spite of the same driving techique on the same roads and same travel patterns. Regards.

I have previously owned an RX400h for four years and was getting close to the combined economy figures regularly, namely 32 to 33 mpg against published figures of 34.9 mpg. Admittedly thus was only achieved by not pushing the car hard and mainly driving on country roads with some town driving and very little motorway driving. I am now driving an RX450h, which has only 4500 miles on the clock, but I find it very difficult to match what I was getting from my RX400h, even though the 450h should return about 10 mpg better for combined driving. I am driving in the same manner on the same roads as I had been with my 400h, but I'm consistantly getting only 29 to 30 mpg. I have been around long enough to realise that manufacturers published figures are always over optimistic, but I was consistently getting within a few percentage points of the RX400h combined figures,whereas I'm not getting better than two thirds of the published combined economy figures for the RX450h. Are there any other RX450h owners out there who are getting anywhere close to the published economy figures, or are they close to complete fiction?

I have owned an RX450h Premier model for about seven weeks and I am very dissapointed with the fuel performance. See below my explanation as sent to the local Lexus dealer, who have tested my car and found no fault. Published fuel consumption comparisons for RX450h and RX400h in miles per gallon. RX450h - Urban = 42.8, Extra Urban = 47.1, Combined = 44.8 RX400h - Urban = 37.2, Extra Urban = 31.0, Combined = 34.9 Apparent improvement for 450h over 400h = Urban = +5.6, Extra Urban = +16.1, Combined = +9.9 I previously owned an RX400h for over 4 years and I was consistently getting 32 to 33 mpg. This is 2 to 3 mpg less than published combined driving figures (between 6% to 8% less). Also, I bought an RX400h for my wife and she is getting around 31 to 32 mpg regularly. So far I am getting between 29 and 30 mpg from my RX450h. This is about 15 to 16 mpg less than quoted for combined driving (between 34% to 35% less).. Whilst accepting that it is unrealistic to expect to achieve the quoted figures I was getting very close to the combined quoted figures for the RX400h regularly, yet I can’t get close to the published figures for the RX450h at all, in spite of having the same driving technique and travel patterns. This is why I am concerned. Comments. Having driven my previous car the RX400h for more than four years I have become quite accustomed to regularly getting between 31mpg (worse case) and 36 mpg (best case). The only times I have had less than this was for motorway trips at high speed, where I got between 28 and 30mpg. My average was in the region of 32 to 33 mpg and the 36 mpg figure was only reached if I had included at least one trip to York (on A1079) between fuel fills. These figures have been frequently achieved throughout the winter months as well as the summer months, I believe the reason for this is that the York trip involves lots of cruise control driving with the speed set between 45 and 55 mph, which means not much accelerating and decelerating and fairly constant speeds. Also we usually travelled at non peak times, with little traffic conditions. As I’ve stated previously, I used the “Brake” mode whenever possible to help on decelerating and frequently cover many miles without needing to touch the foot brake, in the belief that this driving technique should help to recharge the propulsion battery and enhance overall economy. The net result is that I nearly always achieved an mpg figure which was within a few percentage points of the combined published figure for the RX400h. Namely I was getting 32 to 33 mpg against 34.9 published for the RX400h. This was achieved across nearly all my driving, the only exceptions were for occasional motorway driving, or extremely bad weather conditions. Most of my driving is on country roads or around Hull, with a few trips per week of less than 10 miles duration, which obviously entails an undue proportion of cold engine running. My driving speeds on country roads is usually between 50 and 55mph. Nothing has changed in the way I drive or where I drive, but I have a new car, which has published economy figures considerably better than the old car, so, naturally I was expecting some improvement, but I am getting significantly less mpg, although I did just manage 34 mpg on a round trip to York from a refill, but this is now being averaged down by more normal driving. My conclusion is that there is some problem with the set up of the RX450h or the published figures are a sham. Were the published figures for the RX400h achieved using the same test parameters as those for the RX450h? I am quite environmentally concerned, to the point of having a Ground Source Heating system at home and I am installing solar heating to supplement this, so the idea of changing to a more fuel efficient (although very expensive) vehicle suited my objectives, but it seems this has somewhat backfired and I now feel I am being fobbed off. Over the last few years I have been more than happy with Lexus, barring a few silly niggles, but I now feel quite misled and disappointed, as a good part of my decision to buy the RX450h was based on the expectation of even better consumption figures than those achieved on my RX400h.