1999 q45 fuel economy

[mfarhan_86]

Hi i have a 1999 q45 i have noticed that the fuel economy i have experienced is below average and below what is expected of the car. I am currently achieving about 5 km/litre and i am using premium gas and have synthetic oil in the engine. I also recently had the spark plugs and the air filtre replaced any help or advised will be very much appreciated.

[maxnix]

Might surprise you, but most of us south of the 49th paralell think in imiperial terms - i.e. mpg.

Sounds like you are not too far off depending on type of fuel, warm up times, length of trips, and per centage of highway driving.

[mfarhan_86]

hey yeah i thaught of that but i didn't want to calculate mpg so it will actully work out to be about 11.8 mpg does this sound about right yeah my driving is mostly withing the city and it is a realatively small city so mostly small trips.thanks for your reply.

[Falkdesigns]

That's about what I get then, roughly 12 mpg and I drive with quite a lead foot too.

On a road trip I get about 20 mpg @ 85 mph.

[chinesevoltron]

I'm not sure about the engine type, but my 94 model gets about that 11 mpg city.

[Skibane]

it will actully work out to be about 11.8 mpg

Most of my driving is city - usually less than 4 miles between cold starts. Winter city mileage has never been less than 15 MPG, and typically runs above 16.5.

Even though Ontario winters are much, MUCH colder (and winter gas formulations may be different that far north), 11.8 MPG sounds a tad low.

Have you experimented with different gas brands?

Is the fuel/air tract in good condition (occasional BG-44K treatments, clean MAF sensor and intake manifold)?

Is the vehicle parked outside overnight?

If the engine is in excellent tune, it might be worthwhile to install a plug-in electric block heater - spend 15 cents worth of electricity to pre-warm the engine for a couple of hours before driving it (and save $0.50-$1.00 worth of fuel as a consequence).

[mfarhan_86]

Thanks for the reply. I have tried different brands if gas without any noticeable change in gas mileage. The reason i find this mileage low is i had a Lincoln continental before this car which had a bigger v8 a 4.6 litre this as we know Q45 fy33 has a 4.1 with variable valve timing which should further improve fuel economy regardless of that i used to get better mileage in the Lincoln about 18 mpg. I haven't used any treatments in it what should i use? How can i clean MAF sensor and intake manifold? and yes it is parked outside overnight i will definately be calling around tomorrow to see if i can get a block heater installed.Thanks again for your help guys i really appreciate your time.
Modified by mfarhan_86 at 4:58 PM 2/18/2007

[NyRider]

I get around 16mpg and thats with stp fuel line and injector cleaner at every fill up plus im in ny I've read we have the worst gas 2-much ethanol - premium over here at hess is $2.79/g anybody else got me beat

[StarPD]

Hi i have a 1999 q45 i have noticed that the fuel economy i have experienced is below average and below what is expected of the car. I am currently achieving about 5 km/litre and i am using premium gas and have synthetic oil in the engine. I also recently had the spark plugs and the air filtre replaced any help or advised will be very much appreciated.

I'm now driving a 2005 Q45 that seems to get around 16 mpg city and 20 mpg highway.

My last Q,a '94 Q45t produced similar mileage, 17 city and around 22 highway.

Then my brother drove it on a trip from Phoenix to L.A. 135 MPH all the way both ways. I think that must have seated the rings, since afterward, mileage climbed to around 19 to 20 city and 23 to 25 highway. I then took it on a 7200 mile trip through 19 States, all on regular US highways, no Interstates, and visited family in Chicago, then Michigan.Average fuel mileage for the entire trip was 25.5 mpg, including all local driving and the usual slowing down for small towns along the way. As best I could estimate, it was getting around 28 to 29 mpg on the road.

I intend to drive my new-to-me 2005 hard for a few hundred miles to see if it seats the rings the same way and improves the mileage.

[mfarhan_86]

i was thinking of trying the fuel injector cleaner but i didn't at first because the manual says not to use any additives but 11 mpg is not very nice specially when i am a student. I do try to fill up at gas stations that don't have ethanol because some gas stations say they have up to 10% ethanol like shell gas stations and some don't have any indication of ethanol added i am hoping they don't add ethanol, this is another thing manual says not to use fuel with ethanol in it. Well thanks for your advised will try the injector cleaner next time i fill up the 80L tank with todays expensive gas.

[mfarhan_86]

20 mpg i would love to have that kind of economy coming from my car. i am going on a trip on the weekend not very long about 300 km one way but 135 miles that is like 223 km/hr that is FAST i will try but i dont think that is going to happen in a 100 km/hr speed limit zone. I just hope the gas mileage changes i don't understand why it is so low when the car runs simply great thanks again.

[Goodstuff]

I too have been frustrated with my mileage lately. I have a 98 that has been in my family since it was new. I have noticed just in the last few years my mileage dropping from an average of 17-18 to about 15. I used to be able to get 22 or 23 on the highway now Im under 20. I change my air filter every year too. My dad is an old school mechanic so I dont know if his suggestion holds any weight but he suggested having my fuel injectors as well as the oxygen sensor tested. He claims that fixing either of these worn out parts will solve both my mileage and my performance woes. Also I am in Illinois where we have 10% ethanol added to our gas.

[Q45tech]

as we know Q45 fy33 has a 4.1 with variable valve timing which should further improve fuel economy ????

The purpose of Q45 VVT is to increase the mid range [2500-4500 rpm] torque under WOT and to smooth idle......this would not improve MPG.

[Qproject]

personally I'm tired of these older 8 banger gazz guzzlers.

my next car will be a 2007 lexus ES350, nice big car, stable 21 mpg. done deal.

[maxnix]

personally I'm tired of these older 8 banger gazz guzzlers.

my next car will be a 2007 lexus ES350, nice big car, stable 21 mpg. done deal.

And boooooorrrring beyond tears.

If you really want a guzzling V8, look at any pre 1990 American one.

[elwesso]

20MPG highway is pretty good for a 4.1L making 260ish HP...

Remember your fuel economy when its really cold will be worse for a few reasons....

1. IN climates like Canada they have reformulated gasoline which results in lower MPG during colder months.2. It takes longer for all the fluids to get to proper operating temp= more friction, especially in the rear differential and transmission.3. The engine takes longer to warm up and sometimes may not even reach operating temp during its driving cycle.... This puts the ECU in warmup mode longer and thus gives less MPG..

[Q_SHIP]

Im seeing about 20-21 MPG.

99% freeway driving @ 85.

[BadQ45t]

Glad to see some honest MPG estimates, I can get as low as 12 when I'm driving my 97' in LA like Kevin is geting, I probably have the same right foot problem he has...in the Bay Area where the traffic is much less intense (and I live in sort of a rural area) I do get a mixed 18-20 when I'm at home, I can get 23mph if I drive a strict 85 or less on I5 when as little WOT as possible....but WHY DID I BUY A V8 anyways, for the gas mileage.

For those of us that are old enough to remember, remember the 70's firebird and camaro's that got 7-8mph!!!! Come on, even 16-18 is amazing for a 4,000 pound car with a V8. You want gas mileage, get a Prius, I'm not impressed with the ES350's 21mph, what are you going to save annually? I say you want the mileage, go for a 4 banger Altima or something, once you hit 3.5 liters it is all about the same range.

[Falkdesigns]

^ agreed.

Plus the new ES is just fugly IMO, it's like a bunch of egg shapes smashed together.

Now throw me the keys to a new LS460-L and I'd toss my Q any day! *ducks under desk*

[BadQ45t]

I agree, the ES is bizarre looking....the only weakness in the new LS is the braking, the thing sucks in that deparment, but I like the syling, the interior is amazing, love the power and 8 speed transmission. My Dad is ready to turn in his 04' LS430 in Sept for a LS460 and I'm looking forward to driving it

My dad is going to have his LS430 come off lease, 3 years and only 28k on it, he wants me to buy it but it is white, I know there are alot of guys here that love white cars, I'm just not one of the, plus the LS430 is such a dad's car!

[Qproject]

u know what your right.

then a prius it is!!

Glad to see some honest MPG estimates, I can get as low as 12 when I'm driving my 97' in LA like Kevin is geting, I probably have the same right foot problem he has...in the Bay Area where the traffic is much less intense (and I live in sort of a rural area) I do get a mixed 18-20 when I'm at home, I can get 23mph if I drive a strict 85 or less on I5 when as little WOT as possible....but WHY DID I BUY A V8 anyways, for the gas mileage.

For those of us that are old enough to remember, remember the 70's firebird and camaro's that got 7-8mph!!!! Come on, even 16-18 is amazing for a 4,000 pound car with a V8. You want gas mileage, get a Prius, I'm not impressed with the ES350's 21mph, what are you going to save annually? I say you want the mileage, go for a 4 banger Altima or something, once you hit 3.5 liters it is all about the same range.

[BadQ45t]

QProject, i see you live in LA, the gas mileage is the worst in LA!!! I am tryin go setup the wife for an Altima Hybrid to replace her Sentra in 2 years, the 185 HP engine with the Toyota electric system, that seems like a great compromise.

[Q45tech]

Research the new 2008 EPA numbers note the Nissan Altima 4 cyl now get better mpg than the Camary with identical engines...................the truth is about to come out concerning normal TYPICAL MPG................so many will be so dissappointed with more accurate numbers.

The new 2008 M45 has a 21 highway 15 cityCrown Vic 23 15Titan 17 12G35 24 17

WHEREAS old 90Q were 22 16

http://kiplinger.com/tools/gas_mileage/