How can I get better fuel efficiency

[Tophatchef]

I've got an 1989 xj6, and it's only getting 16 mpg. How can I get more? Gas prices were hurting me before, but now it's been getting worse. What are some short, and long term possibilities, and some cheap, and expensive gas saving tips?
Thanks.

 

[judow]

I almost chuckled when I saw your post and was want to say perhaps you aught to consider a 'smart car.' After I got over my somewhat weird sense of humor, I got serious. Please check out the following two sites.

https://www.fueleconomy.net/feg/noframes/1852.shtml

https://www.ciao.co.uk/Reviews/Jaguar_XJ6__5109859

I guess the only thing you can do is simply smile and admire your Jag as you put in the petrol.

 

[Tophatchef]

Smart Car, that is funny. The jag eats smart cars.

 

[Keoke]

Jest play like you love it!!--Keoke-- :laugh:

 

[Deleted member 8987]

Heck, I've got a Jag that when new allegedly got 30MPG on the highway.
Still gets better than my flatheads.
This Jag passes lots of gas stations.

2.4L and 3100 pounds probably makes the difference.

16 isn't bad.
Around town, my flathead pickup gets that.
At 55, in overdrive, my 50 Tudor gets 26.

 

[Genos2]

My '92 XJS V-12 convert got 12ish mpg,sometmes 1 or 2 more cheers Genos2 P.S, it was 5.3L

 

[Exotexs]

here's some tips, I use these parts in my '84 and my '65 Jaguars. I am not preaching in underwear. There are no cheap solutions. I get 525 miles out of my 2 tanks on highway trips, at 70mph on cruise. During cooler weather, I've pushed it to 540 miles before needing to stop for fuel.

1) replace the air filter with a K&N air filter. AutoZone.

2) replace the spark plugs with SplitFire sparkplugs. I don't have the part number for your model year, but you can find it in their website. AutoZone sells the SplitFire plugs on order. They come pre-gapped. just remove the old, and install the new.

https://www.splitfire.com

3) keep the oil and oil filter fresh. Burnt oil equals bad mileage, engine don't like it. Use the recommended oil for your engine and the ambient temperature where you live. (see Owner's Manual).

4) when was the last time you replaced the Oxygen Sensor? You should replace them every 40k miles. After that they give false readings. AutoZone.

Ex

 

[LarryK]

Drive it like you have an egg under the gas pedal. Anticipate braking and use them lightly. The car might mash Smart Cars, but you pay the price for smashing the pedal. These cars are 4000lbs of raw metal and it takes some fuel to move them. My V12 XJS got 20 on the highway ( long trips ) and 12-14 in the city. Mash the pedal and I saw 3-5 on the computer. My XJ6s got 12-18 tops. Heavy cars, like driving a truck but better.

 

[Tophatchef]

Alright Ex, thanks for that advice, I'm probably going to Advanced Auto tomorrow. I'd go to Autozone, but they are a distance from myself, so I don't think that will happen, but maby Saturday.

LarryK, With regards to mashing the pedal, it's so much FUN! My computer tells me 2mpg when the pedal is to the floor.

 

[Exotexs]

Advanced Auto Parts never have any of the good stuff in stock, and their prices are higher. You can also check at AutoZone's website.

BTW: SplitFire plugs have a 30-day Guarantee, if you don't like them, return them for a refund. Tell me what other company does that. Do not buy the Platinum plugs, get the Copper plugs if you're going to try them. Another thing I experience with SplitFire plugs is quick starts in both my Jags, the engines seem to like those plugs!

Another tip:

keep the tire pressures at maximum. I keep mine at 33. These tanks move easier when the tires are not like marshmallows.

Otherwise, enjoy burning gasoline while there's still a supply! Tomorrow never knows. I have a Schwinn bicycle ready just in case.

Ex

 

[Tophatchef]

I will probably go with the cheaper option first, and then the more expensive. Is it fairly easy to replace the spark plugs? I was very pleased when I saw the price.

 

[Exotexs]

you have never gapped and replaced spark plugs before?

<span style="font-size: 23pt"><span style="font-weight: bold">STOP!</span></span>

this is not a job for guessing. All Jaguar engines have aluminum cylinder heads and aluminum is very delicate when unscrewing and installing spark plugs.

Where are you in Florida? (you can let me know by PM). If you are near Orlando, I'll change them for you and you can learn by watching.

Otherwise let an experienced Jaguar mechanic near you replace them.

Ex

 

[Steve]

I used to get 10mpg around town in my old XJ12...... :laugh:

The tip about driving as if you had an egg under the accelerator pedal is a good one, and with practice you can get a lot smoother and anticipate better.

Ex's offer is very generous, one that you should take him up on if you can. :thumbsup:

 

[Tophatchef]

Ex, I am not close to Orlando, more so Palm Beach County. Don't worry though. I am going to wait for assistance from my Father and Brother who are both very experienced with cars. If I have any doubt, I will go see a mechanic. Trust me, I don't want to ruin my luxury motor car over a spark plug.

 

[Exotexs]

great, tell them to not overtighten the spatk plugs, makes it difficult to remove later.

Ex

 

[V6MGB]

Have a look at these sites for some ideas.


https://ecomodder.com/forum/

and

https://www.gassavers.org/

Both are serious sites for fuel savers.

Pete.