Concerned About Fuel Consumption ~ 13 MPG ??
 

Hi, I recently purchased a CPO IS350 FSport with RWD. Past History Fuel Consumption reports all average around 24 mpg. For around the past couple months I’ve been averaging 13 MPG which Lexus Corporate agrees is pretty sketchy so they started a “Case” for the issue but I’m supposed to “do more highway driving before taking in the vehicle”.

I drive mostly in West LA where there’s traffic lights or stop signs every couple of blocks, however I do occasionally take the 405 and 10 >>> “occasionally” being the key word here. Driving is mostly pretty smooth, in Normal or ECO mode, and only occasionally in Sport(+) or using manual shifting. Still, given that, shouldn’t MPG be at least somewhere between 15 to 17?

Have you ever experienced ONLY 13 MPG for around a month? Is this an Extreme Anomaly?? THANKS!!

PS >>> the front tires are getting bald and the dealer offered a new pair of tires which Lexus said might later help with fuel economy but 13 MPG is still pretty drastic...

I can see 13mpg in West LA traffic. Short trip moving only 5-10 mph during rush hour or for most of the day for that matter and circling around looking for parking can definitely result in 13 MPG. The 405 and the 10 aren't any better.

Take a road trip away from LA and see how it does. I'm sure it won't be 13 mpg anymore

Are you going by what the computer is telling you in the car or are you dividing your mileage by the number of gallons of gas you have put in? Ya know, the old fashion way.

Most of my driving is suburban areas with traffic lights and such. The speed limit is mostly 45. I rarely get on the interstate and I do use Sport+ more than necessary.
I'm always 20-22 mpg based on what the car says - and have been for 3 1/2 years. I have watched it drop pretty quickly while sitting in traffic though.

I suspect 13mpg is because of sitting in traffic also. I can see you getting that on short trips where you sit in bumper to bumper for an hour just to move a couple miles. Also expecting you have the air conditioner pumping which uses gas.

Try calculating your MPG for a full tank. Fill up, save the receipt. Reset trip meter and then do a quick math calculation at the end of the tank to determine the mileage over the entire tank and not just a single trip.

I had this issue and it confused me too. Turns out 13mpg is the default the computer resets to if you reset the mileage. Like even if you are getting 30mpg on the interstate if you reset it while driving it shows 13mpg. It goes up or down from there. As I drove more mine went up to 21mpg on my commute. Do the math manually or drive it for a lot longer and DO NOT reset the computer again until it settles on a number other than 13mpg.

What does the computer read for lifetime average? That's what you need to look at. "After reset.

If you are looking at "After Start," then yes it will read drastically lower after LA city driving. My IS200t reads about 14-16mpg after a single trip on surface streets with stoplight traffic. But freeway mileage is ridiculously good. Got 37mpg the other day after highway w/ ac on about 40 miles. "After Start" w/ passenger

My lifetime average reads about 20.8. A little on the low side but I tend to floor it a lot.

That doesn't look much better than my 350 at 18mpg. I drive like I stole it too :o

I get about 18-19 mostly city in the IS 300, with the usual flooring it :)

I just use the "After Refuel" option. I'm only interested in recent history, and it's easier than manually resetting the mileage.

yeah unless you do mostly highway, the 200t doesn't really offer much MPG benefit over the 350, if any at all. seems to be a wash for most.

Funny how the BMW 2.0 Turbo in the 328i (and now 330i) gets way better economy around town--and bamboozles the 200t in power too! (and the IS350 for that matter)

Agree, but my understanding is after you reset, in calculating the current//latest MPG report, over the course of a month, the computer takes into consideration and averages out ALL >>> stop & go traffic, sitting in traffic, shorts trips, long trips, city driving, highway driving, etc, since the last reset, which should approach the IS350 standard.

West LA is around 4 miles from the Pacific, so opening the sunroof or windows is usually satisfactory over the need for AC. Should have stated in the OP that AC is usually off.

I would never be asking if some mileage is 'reasonable' based on city driving. Cities, patterns of driving are so different, LA being a specially bad place for driving (per my experience). Perform a simple experiment, wait until traffic dies down, say around midnight and take her on a freeway. Set on cruise control at say 60 mph, watch the fuel consumption page and within 5 minutes you will know if there is anything wrong with your car.

Yeah I'm averaging 18mpg according to the dash computer. After next fill I will do the math on paper. I'm hoping after the first 1000 miles or after the initial break-in period car will settle and my mpg's will improve.

I have a 2017 AWD IS300 and have been varying the rpm's according to the manual. I drive 50/50 highway and bumper to bumper city traffic. 18 mpg's I can live with, I would not be satisfied with 13 mpg's under the same condition.