handogg

I recently bought a 2004 LS430 with 83k miles. I just filled up for the second time at the station and calculated MPG to be 12 miles per gallon. Can this possibly be normal ? I live in Las Vegas and I do a lot of Stop n Go driving with a minimum amount of idling. No warning lights. I use shell premium gas. Are there any tips or recommended maintenance that can help get the MPG up to 18 City like others on here ?

Thx !

2KHarrier

My wife drives our '05 and 97% of her driving is around the city in stop and go traffic. She routinely shows 12.5 to 13.5 as the AVG MPG. She's a bit of a lead foot, and coupling that with lots of short trips, I'm not surprised with that mileage.

As a comparison, I do probably 95% freeway driving in the '01 on my commute and I'm averaging 27-28 MPG.

It's possible it is a normal reading, but it wouldn't hurt to do a few things that could improve the economy (air filter and clean the throttle body come to mind..)

Johnhav430

I would try this.....take the vehicle onto the highway, and get up to about 70 mph, or 65......now set the cruise, and reset the mpg computer. Try to go at least 20 miles without canceling the cruise. I would say that the vehicle should return 28 mpg. Even 26 would be acceptable. On a couple of occasions I've been able to do the above for 70-100 miles, and I even saw 31 at some points, but it leveled back to around 28.

As far as 12 mpg, it sounds low, but would not be impossible. Say you filled up in Manhattan, and never left the island, it's possible. But in order to do a reality check, the stop/go nature needs to be removed. Just keep in mind, while the 2017 Accords and Altimas and Sonatas of the world are getting real world 26 in the city/combined driving, we would likely be getting about 19, imho. Our 8 cyl. and 2000 technology does come with a penalty...

toddmorr

sure you calculated it correctly? What does the dash readout tell you....that's more accurate.

Bocatrip

Yes it is totally normal for your type of driving. I do 98% city driving with a fair amount of idling as well Always Chevron 93 octane and get between 12.5-13.5 mpg for years. I just took two highway trips to a local airport mixed with my city to get a whopping 17.9 mpg! Our cars are huge boats with 8 cylinder engines and a 5 speed trans. What do you expect? I wouldn't trade down for a few extra mpgs in exchange for the amazing comfort and reliability I experience from my aircraft carrier! I love my LS43O regardless of its thirst for petrol.

Johnhav430

Another tell is the avg mph. I've watched it for years (not just with the LS430), for my commute, month after month after month, it gravitates to about 25. That's where I get 19.x mpg. When I took the business trip to CT, my avg mph was in the high 50's, and that's where it was 26.x. Results absolutely vary with the stop/go and how much of it. That's why level the playing field and drive on the highway, the car does 28, it's normal. This isn't your normal drive so you won't get it, but you know it's there. Try to envision your mpgs at 0 mph, they're pretty bad. Look at it like a batting average. Once it's been established, another 4 at bats isn't going to move it much. Octane doesn't have anything to do with it, as that measures predetonation....

5t341th

iTrader: (16)

i get about 14-15 with my regular commute which is 90% city

Bocatrip

Bottom line.... No Prius here.....But an absolutely Luxo autombile. F...k the mileage.. Just enjoy the ride. I have for the last 8 years! Not going to be easy to find a car like the LS430!

Gronemus

I think I can trust my calculations much more than what the car calculates. As long as you fill you tank up to roughly the same point you will end up with a more accurate figure. I usually fill my tank up every 400 miles or so. If I happen to miss that same point by 0.1 gallon it would only translate into a roughly 0.11 MPG error.

The cars computer can give you a good ball park figure but I generally find that its off by about 0.5 MPG. As usual, YMMV...

handogg

the computer "tank avg" does say about the same thing...

2KHarrier

Fuelly.com is what I use and it seems to be fairly accurate to the vehicle computer. Like Gronemus stated, it's off by half a gallon or so..

Johnhav430

I've noticed myself....the computer "is" accurate...this is by comparing the miles traveled, the mpgs by the mpg computer, then calculating the gallons that would have been consumed. This matches the pump to about 0.3 gal. On the BMW, doing the same, the computer matches the pump to about 0.1. On my wife's car, it does not match. The computer is unfavorable by quite a lot, buddy says his Linc Navigator is the same thing--the pump does not lie. Her car also has a gallons consumed. If it says 18.3, go to fill the car, and it usually is about 2 gal less that goes in. Why? I dunno, has to do with the way the computer is making the calculation. There is not a meter measuring the actual fuel, it's extrapolated...and Lexus and BMW are accurate...my .02...

What I'm trying to say is if you say you'll give me $500 if I can get my car to do 12 mpg, I will do it. If you say I will give you $20,000 if you get your car to do 12 mpg on the highway, at 70 mph, over 50 miles straight, I won't even bother to try, because it won't be able to get less than about 26-28...

AJT123

If it's nothing but gridlock you're driving in, 12MPG is normal. I got about that or less when I lived in Los Angeles.

Aron9000

And I thought the 2JZ-GE in my SC300 had a drinking problem lol. That car does 17-19mpg in town, maybe 22-23 mpg on the highway. Then again I drive fast at 80mph, I'm sure it would do better if I slowed down. Its the 3 liter straight six with a 5 speed manual btw

handogg

It's possible to get LESS THAN 12mpg.. ??? I still can't believe it and am convinced something is up with the car. I just finished the DIY ATF (see other thread).. will do the spark plugs and see if that helps. Once I shut the car off, there is a smell coming from the car.. I want to say it's unburned gas but am not sure.