I'm looking for some help on getting better gas mileage out of my vehicle. I've researched the forum and tried all the suggestions listed. I got the car this past xmas and it started out getting 25 mpg. Now it's down to 17mpg going on 8 months, which I find mind boggling.
Premium gas of course. I use the auto-shift to slow the car down, and use it to make sure I don't accelerate over 2000rpms when I take off. (I feel like somebody's grandpa) The oil has been changed and I reset the trip computer everytime I fill up.
I am at my wits end and would appreciate any suggestions as filling up my tank is killing me! (currently unemployed)

 

the TL is heavy at 3500lbs
it takes a lot for her to get going from stop.

so, if you're driving in town, with lots of stop and go(stop signs, stop lights, etc.) your fuel economy is going to take a hit.

Please post up what your MID says.
what is your average MPH?
what is your average MPG?

 

BAD.

I would look into your driving area(streets / lights etc) Re-route an alternative to help increase you MPH average. If you have a very low MPH you will see a very very low MPG.

 

Justin is right about city driving with stop/go traffic.

17MPG is about average assuming you are doing short trip city driving. Also, how often do you reset your MID?

If you've never reset it you won't be getting very accurate results. Since I usually only drive around town at low MPH, I put the car into the shiftronic mode to push the car into a higher gear (5th gear @ ~38MPH) and to help with start/stop at traffic lights. I've noticed it has improved my mileage to about 19-20MPG.

 

My trips are usually no more than 10 miles. I live less than 2 miles from dc and dc is only so big. I reset the trip every time I fill up. I've been doing this for the last month and a half, hoping that it will change. I don't let the car go under half a tank either. But this is causing me to fill up once sometimes 2x's a week.

 

You should not be using the paddle shifters/shiftronic to shift at that low of RPMs. You are putting more stress on the engine by shifting at too low of RPMs.

 

what is your average MPH? Is about 23 city, 26 hwy
what is your average MPG? Average is 17. When I fill up it will start at 19 and nose dive to 16 and go back up to 17 within a day or two.

I drive mostly in the city (washington dc). I notice when I on the freeways it will go up to 19. But I'm usually downtown so I'm not going that fast. Even on the freeway I don't go anymore than 65-70 if that. (depressing)

I only use the auto shift breakdown say from 3rd to 2nd. So I should leave the shifter alone?

The #'s didn't take a noticeable dive until late May early June. About every two months since Jan. It went from 25 to 23 then to 20/21 and then 18 and now its just stuck at 17.

 

Yeah down-shifting with an automatic transmission is never good for the engine. Gas mileage could be a result of a bunch of different factors such as tires/air pressure, oils and fluid levels, or the length of the trip.

23MPH is a little under what mine says (25) which is from city driving only. If your taking short trips (like to the store or something) the engine doesn't have enough time to warm up so that can also take a hit on your mileage. Take a look at this thread to see if any of these tips help you: https://acurazine.com/forums/3g-tl-2004-2008-93/tips-better-gas-mileage-815785/

 

04desertmist - I would try to reduce the weight of your car.

3500 lbs is a lot of weight, try this method. Only have your car at Half full tank of gas, and that is your new "full" saving you over half the weight from a full tank versus a half tank. It's annoying but less weight will be better on your MPG.

 

Gotcha, I break it down like I break down my 5 spd. I'm not going 60 downshifting to 30. I only use it from like 40/30/20 4th/3rd/2nd.

I've got to run a few errands around the city, just filled up the tank sunday night and its been sitting. Will repost new MID in a few hours.

 

My Average MPH 17
My Average MPG 14

 

Everytime your car is stopped at a traffic light, it's factored into the mpg. If you do a lot of stop and go and never get a chance to cruise for an extended period of time, it will show crappy mpg. I will sometimes drive a mile or two after filling up and resetting the mid so I'm at an area with no lights or I get on the interstate.

 

I mean upshifting. It's bad to shift the engine to a higher gear until then engine has reached high enough RPMS. It causes extra and unnecessary stress on the engine. Our engines get most of their power/torque in the higher RPMs. By shifting before you hit 2k RPMs in any given gear, you are stressing the engine uncessarily.

Think about riding a geared bicycle and skipping from 1st gear to 15th gear...

 

another gas mileage thread? thank goodness!!

 

All I can say, is your commute must have changed to explain your drop in mileage.

Your car is running fine. The problem is your AVERAGE MPH is pretty low. For comparison, my MPH is usually 26MPH and I get 18-19. So 17 MPG at 23 MPH city is about right. If you search on my login, you'll find a thread that I gave a formula for correlating MPG to avg MPH.

Suggestion: try a different commute route or try cutting the motor at long traffic lights. You'll get about 1MPG doing the motor shut-off and possibly another MPG with a different commute if possible. Remember idling at a traffic light is like getting ZERO MPG while you're stuck at that light.

 

I do nothing but city driving and I average 18mpg. My route to school does make me sit at stop lights a lot.

I can get up to 30 mpg if I go on long high way trips.

I am getting misfire codes in cylinders 1 and 5 so I'm planning on changing my spark plugs. Hopefully that can help me squeeze out a couple more mpgs.

 

Thank you. My baby has been acting 'shifty' since I've been using this shiftronic bs. The engine is always 'jumpy' and never wants to get 'in' gear. But I've also been babying it and not throttling thru my gears.

 

LasCosta..... Yes, thank you. I did not take this into consideration. I have been laid off since memorial day. That is when I had a significant drop in MPG's. Before this I was driving my car daily to/from work about 20miles each way (since I drove carpool) with a mix of hwy and city and dartin/dodgin thru traffic and speeding. Now all I do is drive to/from my errands during the day which are much closer and I don't drive as fast or far and it sits for 2-3 days at a time.
This never crossed my mind as I wouldn't have thought daily driving compared to sparingly driving the vehicle could cause such a drastic change.
Maybe I need to take a good road trip this wknd down south at 90+mph!

 

I read most of them and still needed some input. Thanks tho!
Being unemployed and paying $4.20 for premium will make you try to reinvent the wheel.

 

It's not that you are driving infrequent per-se. It's what you're doing when you are driving. Your average MPH from the MID says it all: you are stopped a lot of the time, idling, burning fuel.

Since you're in DC, public transportation might be a better way to go if you can't afford the gas on a TL.

If you insist on driving, try cutting the motor at long lights. I did an experiment a few years ago and could save a whopping 1MPG doing that on one of my commute path (driving the coast to work). This is one reason many car makers are adding the start/stop feature to non-hybrid cars now. I then found taking the freeway, while less scenic, was the way to go and improved the MID value by 2MPG and raised my average MPH by 3 MPH per tank.

I understand the importance in your particular situation, but you must also understand that your car just didn't degrade in fuel economy. Lots of people get 17MPG and they usually have one thing in common: a <30MPH MID speed. Lots of threads have had this fact brought up, so it's surprising you didn't find that information, actually.

 

Using shell v power 93 I get 25 mpg in the city.....before it was like 19.

 

That was the only thing I didn't see when doing research. B/c I don't avg anything over 30 n my MID. I'm usually betwen 23-26. I guess once I get back to daily driving things will improve.

I appreciate all of the input!

 

Yea, I'm a kinda the cheapest premium I can find type of guy! Shell is the most expensive gas in my area. Usually I'm a BJs or Citgo filler upper.

 

Why do people make outrageous claims in mpg threads? You did not get a 6mpg bump from swapping brands of fuel. This kind of gain can only come from going from 87 to 93 octane and even then it would be hard.

Just like every mpg thread, average mpg follows average mpg period.

Upshifting too soon won't hurt the engine but it makes a lot more heat in the transmission and hurts mpg. You're causing a ton of slip in the converter and losing the mechanical gearing advantage. In other words, about the same rpm, more throttle required for the same acceleration.

 

^^^

my car shifts around 2800-3000rpm when in D....i tend to shift at 2200-2500 rpm depending on the load on the engine....shifting early doesnt mean shifting at 1500 rpm....let her rev a little bit

 

If its an older car with fuel issues, I would consider replacing the O2 sensors. The sensors in these cars seem to need replacing every 60-100k or so.

 

I've been shifting at 2000, however since I've been using the shiftronic I have been getting a lot of slippage when I don't use it. I will stop using it.

 

Keep my tank at half full? Really? I don't keep anything in the car but me. My trunk is empty.

 

A thought, I only have 84k on it, and I haven't had the timing belt/pump changed yet either.

Thanks for all of the input. I've been driving a little harder and it's gone up to 20MPG. So I'll stop drivin miss daisy.

 

I think driving like miss daisy actually helps. My fiancee (who drives like a granny) has been driving my car for the past two weeks and she's averaging 27 MPG on a tank whereas I would average about 22 MPG.

Other notes I have a TL-S w/ 67k miles that I only fill with Chevron 91. UR pulley and RV3 J-Pipe so I'm sure that helps a little with gas mileage.

 

I drive in an area where speed limits are 40 for the most part and I like driving between 40 and 45. My AT shifts to 5th gear at just above 45, so I use manual mode just for the 5th gear to make it stay in 5th for the 40 to 45 range speeds that I care. I do push it to 3500-4000 rpm in the lower gears while getting off from traffic lights. I average around 20-21 for mostly this type of city driving.

 

I got AVG MPG is 21 for the last 3800 miles with A/C on most of the time (will post pics later) with avg speed of 26 mph But on the highway I got 31 MPG. OP remember DC is a big city and most likely the traffic light took forever to turn green versus me living in a small town where traffic light took about 2 mins to turn green again so your MPG will suffer than me. I also want to mention some people like to wait for their engine to warm up before shifting into D, this also hurt your mpg, there are many variables associate with your mpg so by compare your mpg versus X person from this forum doesn't help. Variables is describe as follow.

1. Time to take traffic light turn green from red.

2. Amount of traffic within the area that you are driving.

3. Personal driving style (shifting, heavy foot, etc...).

4. Weather climate.

5. City travel or highway travel.

 

I'm in a medium size city, 500K. I get 20-22 around town and 29-31 on the highway...pretty good for a car with the hp and weiht of a TL.

 

Like most every fairly 'high' displacement 'heavy' car, the TL does not get good MPG with frequent stops and starts. If you want better city MPG, get a Prius.

However, it does a good job at 40-60 MPH cruising. You can expect 35-40 MPG at those speeds, assuming you nearly never stop.

 

try seafoaming your engine and half into gas tank. It MAY help

 

I'm assuming the torque converter is about a 2K stall speed. That would mean shifting before 2K is likely less efficient than shifting above 2K. You're probably going to get the best MPG's driving in drive, the manual shifting you're describing sounds like its more likely to decrease efficiency. Don't downshift at every stop, thats just going to unnecessarily wear your transmission. Get a feel for how the fuel cut works and you can best determine when to let off the gas and coast to a stop. This does not mean you should coast to a stop at low speeds, its useless once the injectors are back on. You can usually feel fuel cutoff fairly easily if you pay attention to the deceleration when you lift off the pedal. This likely only occurs at higher speeds, when the torque converter can be locked and maintain above idle speeds in top gear. Moderate acceleration is fine, just avoid low engine loads. If you are doing fairly short drives frequently a block heater on a timer 2-3 hours before you leave will likely give you big gains with no effort.

On short drives with a cold engine and lots of stops, I get 14-15 MPG. It can be even lower fairly easily. Cold engines are not efficient at all. It takes at least 15-20 minutes before the engine bay and intake is hot enough to start getting good MPG's. A block heater can help short trip MPG's bigtime, but you need to plug it in at least an hour before you leave.