Jaguar Forum banner

XJR economy,shocker and retrofitting cruise

2456 Views 14 Replies 10 Participants Last post by  DaveV8
So after 2 weeks with my new 1998 xjr i have a couple of questions. Firstly whats the average mpg for fellow owners? I wasn't expecting it to be great but to be honest its frighteningly bad! When i bought it i heard a few comments like if you're not getting 15mpg you're not going hard enough :) truth is I'm driving it like a granny and barely getting 15!! I do quite a lot of town driving with a few out of town runs & i expected maybe 20mpg with a bit more on a longer run. At this point I've hardly opened it up, So whats yours doing?

Secondly, sometimes when i park up it seems to be sitting down on osf to the point of being very noticeable. I tried playing with the cats & weirdly it seems to sort itself out. I'm thinking maybe a soft or faulty shocker? Any thoughts?
Last question for now, is it possible to retrofit cruise control to a 98 model?
1 - 15 of 15 Posts
On the fuel side of things 15 mpg sounds about right. i get 16ish average. on a good run i get mid 20s.
its never going to be great on fuel!
Your mpg isnt far off, i can get anything from 14-18mpg round town depending on how you drive, on a run u shuold be seeing 22-24mpg, I have a knackered lambda senor though which can make a difference and Ive heard of people gettin 3-4 mpg on top of the figures ive quoted as a result.

As for your dropping on one side the suspension at the front is known to drop over time due to the heavy engine, this can be fixed by replacing the springs, for it to go on one side only is a little strange unless someone has only replaced one spring at some point
17mpg round town, heavy right foot and sticky yoko tyres
I used to get 16 - 18mpg around town and mid twentys on the run. in my old x308 so yours around town sounds about right. You could always try to give the MAF Sensor a clean to get better mpg and also check the air filter is nice and clean.
Thanks for the replies guys, so there's not a magic button to improve mpg? dammit lol

Guess i'll need to get used to it then. As for the suspension, it's a weird one, it's not all the time just occasionally it seems to sit down on drivers front almost like you have a flat tyre. No sign of a broken spring or leaking shocker and the cats seems to work ok. I'm going to see my jag specialist tomorrow to get key fob replaced & reprogrammed so i'll see what he thinks.

Any thoughts on retrofitting cruise?
I find it drinks fuel driving it fast or slow lol. You may as well try drive it fast!
Does the car sit low on one side on a perfectly flat surface? I only say this because I thought my car was sitting low untill I realise that every surface I noticed it, wasn't perfectly flat.
Once on a concrete floor in a garage it, all evened out.
I'm pretty sure I've heard people retro fitting cruise to x308. Jag-lovers might be a place to check if a search here is fruitless.
Well got the car checked today & nothing obvious wrong with suspension etc. My jag guy gave me a strange look when i tried to explain it :) maybe it is where im parking, if i think its doing it again ill take some measurements to check. On the plus side i now have 2 fully working remotes, i can now stop the manic rush to get the key in to stop alarm activating.

One other question, has anyone managed to improve the pitiful dribble that comes out the washers on the wiper?
I think you have a problem with your washer. Mine is powerful.
I think he knows he has a problem - that's why he's asking for help! :)

If the pump sounds like it's working properly maybe the pipes have got blocked over time? Or maybe the nozzle jets just need a bit of a poke?
sorry i should have been a bit clearer, when i operate the washer jet which is on the actual wiper arm (are they all the same?) the water flow isn't great, not a good jet like bonnet mounted jets. So question is do i have a problem or are they all weak? I'll try giving the pipes and nozzles a blow through.
I'd go along with replacing the pump.
When I bought my XJR the windscreen wash did not work. I took the washer tank out and found the bottom of the tank full of a soapy slime from the additive you put in the water for the washer. I cleaned out the tank and took the pump off and flushed it through with warm water and then ran it in a bowl of warm water. The crap that came out of the pump shocked me!
Then flushed the tubes up to the jets.
All works fine now.

Hope this helps
I get 20mpg around town with a semi heavy right foot on the occasion. I went to Belgium in mine last week which was 280 miles round trip from where I live and I was doing 70mph there and back, chilling out, enjoying the ride and my computer in the car was stating 22.3 mpg which I think is wrong because it took EXACTLY £55 in petrol and if you do he maths on the price of petrol it's wrong!

Every car will be different even though we all have the same car but I'm very happy to have a car with a lot of performance figures at 22.3mpg on a long run and 20mpg around town :cool:
1 - 15 of 15 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.