91Q gas mileage

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alex05
Posts: 10
Joined: Fri Oct 24, 2003 9:57 am
Car: 1991 Infiniti Q45

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I bought a 91Q just a few months ago from my dealer. The previous owner had gone to the dealer for all his service so the dealer gave me a copy of the records and I found the car thankfully had a new transmission and new chain guides. The only immediate problems were oil related; I had to have several gaskets replaced and two seals. The car now runs great, but I still have one reservation the dealer could not answer: I get really low gas mileage. I get between 9 and 14 mpg, averaging about 12mpg, with nearly all city-driving (living in LA). When I took a trip to Palm Springs, at a fairly constant 70-80mph, I got the mileage up to 19mpg. I was reading around and, also considering my previous experience driving V8s, thought this was low. So I wanted to ask if anyone had input on what might cause this or if it is normal and, since it is a heavy car with a big engine, I just need to get over it and pay $50 each time at the pump. Any ideas are much appreciated.


timatt
Posts: 109
Joined: Mon Nov 03, 2003 6:30 am

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I purchased a '91Q in October and get 19-20 mpg, during the winter months driving mostly road miles. Since most cars I've owned get a few mpg better during the warm months I think it will be a little higher in the summer.

timatt

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PalmerWMD
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Joined: Mon Apr 29, 2002 3:14 pm
Car: 2004 350Z

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winter gas is not as good as summer gas for milage.

I tend to get 20 mpg on hiway, at speeds around 85mph (22-23 if I reallry try hard to go slow say 75 mph).Thats the best test of an engines health, checking the hiway milage.

My intown milage all winter has been 11 mpg but it didnt bother me, cuz all my trips are 4 miles or less, winter gas formulation, the ECU was always in warm-up mode and some idling of course.

The combination of these factors would even get a 4 cylinder Accord to drop well below 20 mpg mark in in town driving.

Since we have heavy V8 powered cars I feel the numbers are fine.

Fred...:)

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AZhitman
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Not a bad idea to swap out the O2 sensors just in case (they're shot by now).

I see 13-15 mpg in combined city/highway driving...

DAEDALUS
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Joined: Mon Jul 22, 2002 8:50 pm
Car: 1990 Infiniti Q45

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The mileage sounds just right to me. I get a little better in my Q, but with less city diving. I know that on my 5.4L Dakota, I get a very consistent 12-13 mpg week to week, and 20+mpg on long road trips. New O2 sensors make more sense the more gas prices go up. The cost is usually justified around $2/gallon, so at $3/gallon, they should easily pay for themselves.

Q45tech
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Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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Concur that the O2 sensors can drop mileage by up to 15%, usually only 10% , then CA gasoline another 5% then CA traffic as opposed to rural city EPA model and you get to 20% [0.8x 16=12.8 mpg] without AC.

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elwesso
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2007 Infiniti G35 S 6MT
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I get about 15mpg all city on my 94. Hoping to get at least 17-18 with my new o2 sensors (which are coming soon).....

Q45tech
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Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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The RURAL* city cycle EPA numbers for Q are 16 mpg with non oxygenated fuels.

Just a few stop lights and no stalled traffic where you can average 30 mph...............not any city I know of today.Think there is one such place in South Dakota.

alex05
Posts: 10
Joined: Fri Oct 24, 2003 9:57 am
Car: 1991 Infiniti Q45

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Thanks for all the responses. Anyone know where the best place/price is for the 02 sensors for the 91? Thanks again.

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elwesso
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Car: 94 Infiniti Q45t 5 spd
2007 BMW M Coupe
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Goto sparkplugs.com and you can get them there. The short lead is enough for both sides.

I also can get you OEM sensors for a small discount below what Joe has, if your adiment about having OEM stuff. I dont think it makes a difference either way, but I wanted you to be aware either way.

Q45tech
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Posts: 14296
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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4.5 liters of space have to be fed by fuel every two revolutions.

Nothing beats displacement for stucking up fuel. 22 gallons of fuel will last more than twice as long [2.25 x more hours] at idle in a 2.0 liter engine..........assuming same rpm.

The rest of the WORLD taxes users on displacement to force efficiency!Japanese Consumption tax on personal vehicles [CARS] up to 1 LITER 29,500 over 1 - 1.5 34,500 over 1.5 - 2 39,500 = $360 per year consumption taxover 2 - 2.5 45,000 over 2.5 - 3 51,000 over 3 - 3.5 58,000 over 3.5 - 4 66,500 over 4 - 4.5 76,500 = $700 per year consumption taxover 4.5 - 6 88,000 = $800 per year consumption taxover 6 LITERS 111,000 yen= $1,000 per year consumption tax

US GAS GUZZLER TAX IS PAID BY MANUFACTURER AND REFLECTED IN NEW VEHICLE PRICEUnadjusted MPG(combined)* Tax at least 22.5 No tax at least 21.5, but less than 22.5 $1000 at least 20.5, but less than 21.5 $1300 at least 19.5, but less than 20.5 $1700 at least 18.5, but less than 19.5 $2100 * 90Q45at least 17.5, but less than 18.5 $2600 at least 16.5, but less than 17.5 $3000 at least 15.5, but less than 16.5 $3700 at least 14.5, but less than 15.5 $4500 at least 13.5, but less than 14.5 $5400 at least 12.5, but less than 13.5 $6400 less than 12.5 $7700

http://www.liberalartsandcraft...shtml

I believe paying annually vs lost in purchase price is more likely to make owners think about what engine size they buy.

Q45tech
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Posts: 14296
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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Tweaking the gears [diff especially] can save [cost] a manufacturer $400 even $800 in tax payments to US government per car.


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