About 2 weeks ago I went to Firestone (where I always go) and got my oil changed, tires rotated & balanced and wheels aligned. Since then, I went from getting 260 miles per tank to getting 200 miles per tank.

Everything feels fine on the car. The tires have enough air in them and don't have too much air either. The balance seems to be good as there is no shaking with the car. I checked the oil too and it was fine.

Any ideas as to what this could be?

 

Seems like you're implying Firestone's work may have caused the MPG drop.
Your MPG sucked before at 260.....anyways if the air pressure is up and the tires appear to be wearing and tracking well, then what about the oil brand's weight at the time of change ? When was your last tune-up ? Do ya drive aggressively ? Do ya use premium fuel ? Have ya tried a fuel system cleaner to help clean out the dude's pis in your tank ? Ha, hah....JK, IDK !!!!!

 

 

I've always gotten 260 per tank city in most all of my Acuras. I guess it's the way I drive. I would say I do drive aggressively. As far as fuel goes, I normally go between 89 and 93....sometimes 87. While experiencing this issue, only premium gas has been in the tank.

Yes, when I filled up 2 days ago I put in some Lucas fuel injector cleaner. I just went to the gas station and topped off. I had drove 52 miles and the car took 3.825 gallons, equaling 13.6mpg. I took the negative batter cable off to let the computer reset. I did this because I had lost my fuel cap for a while and my check engine light came on because of that. After I put another fuel cap on the check engine light went off after about 2 days. This was around the same time I had started to notice the decrease in gas mileage. So maybe resetting the car's computer will resolve the issue.

The next step is to drive 40 miles and then top the tank off again to see what the MPGs come out to.

 

Even if you can get it back to 260 miles per tank that's still low.

Spend some time checking out things to get you better gas mileage and a better running auto.
~spark plugs
~air filter
~oil change
~try using seafoam instead of lucas
1/2 can in the crank case drive 30 miles before an oil change
1 can when gas tank is empty
~egr port cleaning (check diy section)

 

How many miles? May be time for valve adjustment.

 

199k Miles

 

Do you have a Type-S? If so, how many miles do you get per tank?

 

How many miles are you guys getting per tank in your Type-S? When I fill up, It usually takes 14.1 gallons.

I'm back to getting my normal 260 miles per tank now. Must'be been some bad gas. Still want to know what everyone else is getting per tank.

 

I don't have a type "S" model, but I always get at least 300 miles leaving it go to about a 1/4 tank. I don't like running any lower, as it's really hard on the fuel pump. If I run to the "low fuel warning" ....I can get 375-400 miles from a tank of mid grade fuel.

 

So is the 375-400 highway miles? I do get 360 per tank on highway.

 

Yeah, at least 75%. So, in all reality your'e doing primarily stop and go short hauls....with a bit of spirit too. In the wintertime and shorter trips, MPG goes to shit, 250-300 tops....no matter what !

 

Yes, I will say that I am a very spirited driver .

 

260 to a tank CITY isnt bad or low. IF it were HWY id say yea its low.

 

What is enough and not too much????

Drive MORE than 40 miles. There can be too much discrepancy with that short of mileage. Drive at min a half tank.

 

Damn y'all, looks like I'm having the same problem again. Before this last fill up, I went 340 miles (mostly hwy) before my gas light came out. After my last fill up on Sunday, I've drove 102 miles and I'm already at the halfway mark. It's been normal driving and I haven't been driving very aggressively.

My car is at 199k miles and the spark plugs were changed at about 120k miles. What could be the issue? Do my fuel injectors need to be cleaned?

 

I am getting about 415 til my fuel light comes on..all highway for me..my best so far is 435 for a tank pretty great!!!

 

Plugs are recommended around ever 100k, but if its sporadic then I would think poor quality gas, or maybe O2 starting to go. But keeping the PM up can't hurt. I will check my mileage next tank but I usually get mid to low 20's around town and mid to high 20's highway and I drive pretty aggressive.

 

What do you mean when you say "keeping the PM up"?

 

You can't be getting that mileage in a Type-S.

 

PM periodic maintenance: timing belt, valve adj., plugs.........
Is there a difference in power when the car is drinking that much gas?

 

Nope, no difference in power from what I can tell. Not sure what's going on. The tire pressure is right and it's not time for any PM.

I'm not scheduled to do my timing belt and spark plugs until 225k miles.

 

i have 130k on my TLP and only receive about 250 miles on full tank @ 93 oct. but i'm 50/50 when it comes to city/highway driving and i have a lead foot

 

TL type S (I/H/P + some other mods) = Get around 310 miles on City and 43X ish on highway...
Sounds like 24-25mpg on city and 31 hwy... I would say 26 combined.
I'm 70% Highway 30% City.

Due to Valve Adjustment (I can hear them cry) but haven't lost MPG by them.

 

Big Cope I'm get pretty much the same mileage as Skimich posted I double checked today. Could be a sensor starting to act up, start with the O2 sensor you can check it with a volt meter on the car.

 

This will have the single biggest impact on your car's overall fuel use.

Also, are you always using the same brand of fuel or do ya jump around ? Try another different top quality brand of fuel for the next couple tankfuls and test the mileage results.

As previously mentioned, any older car will start developing some issues in the way of "PM". However, they can often go un-noticed because the ECU compensates for many deviations. Things like sensors can tend to operate on the edge of their desired range and in turn result in fluctuating MPG performance. Research some things that can affect the air/fuel ratio and evaluate testing of vital sensors and components.

Check the fuel pressure and all the electrical connections. Try some fuel system cleaner. Try driving more conservatively. Etc, etc.......!!!

 

Man I don't know how you guys are getting so much more gas mileage than me...lol. Now, when I say I get 260 per tank (or was), it was measured from fill up (usually 14.1 gal) to the time the gas light came on.

 

I usually jump around between BP, Shell and Exxon. For fuel cleaner I use Lucas fairly often. I didnt use it on this fill up, but I did on the previous one and got about 350miles on that tank with mostly hwy driving.

 

One thing that did happen before this started is that I lost my gas cap. I probably went without one for about 2 weeks and then my check engine light came on. I had it checked and it was due to the gas cap. I put another one on and the light went off in like 2 days.

My mechanic told me that the ECU may have changed the way the car consumes fuel due to the gas cap being lost. So he advised that I disconnect the negative battery cable so the computer could reset. I did that, then took the trip out of town in which I got normal fuel consumption (i.e. the aforementioned 350m on a tank).

 

See the image of my cluster below. See where the hand is and I'm only at about 100miles?

 

The way I record Gas use is like many others do..
Fill complete tank - Reset trip meter A or B - Record how many miles you travel till Gas light went on.

I keep full year records of my gas consumption this is 100% City 2013 Trip to job and back = 28 Miles daily.
Between Jan-Feb = 331 Miles Top / 328 Low
Between Mar-Apr = 322Miles Top / 320 Low
Between May-Jun = 329 Miles Top / 321 Low
Hot Months:
Between Jul-Agu = 318 Miles Top / 311 Low < Valves started to be slightly heard
Between Sep-Oct = 310 miles Top / 307 Low < Valves are beggin to be adjusted

If I used the gas after the Gas light I think I could squeeze a full job trip with it.

 

How is everybody getting such high MPG in their 2G's?

I have a 99 TL and i pump shells V-Power, which is 93 octane and with 50 bucks the needle would either be on the full line or above the full line and i never completely top it off. I drive my car mainly on highways hardly city unless trying to enter the freeway and right when the gas light turns on my mileage would be 250/260 and i would drive it until the empty line, which puts me at 280/300 before i fill up again.

Let me mention this is a 99 Acura TL, which is the 4 speed tranny, so could this be a factor or no? My has car has 117K and is well maintained, with sea foam, oil, sparks etc. I defiantly need a new air filter on my intake, new brake pads and have not change the O2 sensors they hace been the same ones since the car left the lot.

 

Shit I used to get 400+ if I was highway only.

 

Ive gotten as high as 520 on the hwy cruise set between 75-80.

 

Ill Ask Again

What is enough and not too much????

 

Yeah, as Fsttyms1 pointed out....."What is enough" and ha, hah....not too much ! Can't say that I ever had too much of a good thing. Well, except maybe on a rare occasion or Holiday .... a few too many beers, like today !!!

But seriously, you're the master of your destiny when it comes to MPG on our TL's. They can suck if ya have a heavy foot in town and they also can do relatively well if ya are cruising some cross country touring at the speed limit. Keep the PM up !!!

 

I still get +440 miles on highway only, Cruise set at 80mph.
Tires set at 35-37psi always.

 

Your wheels are also going to play a roll in lower fuel economy, added rotating weight. Also consider the weight up put in the car.

 

if you guys are gettign 400+ on highway then what is wrong with my car? is it the 4 speed (D4) tranny becuase all of your guys cars are 5 speed (D5). i havent clean the EGR and i remeber when i had the car at 73K back in 2009 i used to get like 350+ MPG and in 2011 when i had 105K i got the timing belt and etc all changed and i have noticed a weird ticking sound when i am in a parking garage, which sounds like ticking vavles. So would that effect my MPG?

 

It depends how badly the valves are not adjusted.. Mine are starting to click somewhat loud but seems is only the front Intake valves (Which are common to misadjust in high mileage Honda V6s..

The job itself its pretty easy if you know your war around engines.. Honda V6s are one of the easiest engines to work on.