Hello,
I own a 1986 XJ6 known as the Big Girl. Well, I have owned the Big Girl since last September, and as happy as I am with her, she has one issue...gas mileage.
I have replaced the plugs..I tried Bosch Platinums...no go....AC Rapidfires...no go...I went back to the standard...Champion RN12YC. Plug wires are ok...not changed. I changed the rotor and cap...and last week the oxygen sensor. The vehicle has 95,000 miles, and has been well taken of. The past owner owned the vehicle for seven years and only drove it on weekends to play golf...winters it was stored. It does not burn oil...I used synthetic. Actually, it is in great shape...but I can't figure out how to get better gas mileage. Please help.
thanks...rick

Submitted by browder@nuventrs.com on Sat, 05/07/2011 - 14:48

Robert: trying to get some info on FasterJags....probably should have done this before sending Brian a couple of thousand dollars for parts, but in any case it seems that you might know him and can provide some insight as to what is going on with FasterJags. Very nice to deal with when I was putting my order together but now I am not getting any email or voice mail responses. Not normal in my book, but then I do not know the guy. Thoughts?

Submitted by equisr@aol.com on Sun, 04/10/2005 - 16:53

GO TO WWW.FASTERJAGS.COM
Brian is a great guy, made the 1st cold air box for my former 87XJ^
Good Luck
P.S.
If you are interested in fuel economy, Why did you buy a Jaguar?

Submitted by jam@ispwest.com on Sun, 04/10/2005 - 15:38

yes, K&N makes a great filter, increases hosepower and air flow to the engine, I've had mine on since 1994, it's a forever-filter. Rick got one recently for a great price, same price I paid 11 years ago. The Ground Straps I make myself, Rick and John Kenny and others installed them and they have reported benefits in many areas, especially during Idling and in gas mileage. But the XJ-6 is not a Toyota, it is a thirsty refined car , though not a gas-hog by any stretch. But if you wanted a Toyota you would have bought one, right? The best mileage I ever got before installing the O2 Ground Strap was using Splitfire spark plugs, I had them installed for 6 years, then I started hearing about problems with them; since it was time to change plugs, I tried the Bosch +4 Platinum and I don't like them, I think they are no good. I'm going back to Splitfires.

Submitted by jeff.bolmeyer@… on Sun, 04/10/2005 - 15:05

Do you have part numbers for your improvements? I just purchased an '87 XJ6 and will want to make what ever mods that I can to help out the gas mileage. I did not think that K&N made a replacement filter for this car? My email is below. What about the ground strip for he O2 sensor?

Thanks,

Jaguar Jeff
'95 XJS 6.0L Convertible
'87 XJ6 VdP
jeff.bolmeyeratcomcast.net

Submitted by jam@ispwest.com on Sun, 02/27/2005 - 18:25

There's not a lot you can do. I've owned my '84 for the last 14 years and gas mileage has never been a Jaguar benefit. But I started noticing better mileage when I installed a K & N air filter, I did notice a slight improvement. Then I installed Splitfire spark plugs and I noticed another nice improvement. The third improvement was when I installed a Ground Strap to the Oxygen Sensor. I liked the result so much that I developed my own to offer other owners. What is the condition of your Catalytic Converter? How old is it? The catalytic is a gas hog, and if it's past its bedtime, well, go figure. I don't use synthetic motor oil, technicians have discouraged me from using it. I use Castrol 20W50. BTW: I also installed those Bosch PLatinums Triple-something and my conclusion? they suck. The Splitfires were waaaaay better. I lost my money on those Bosch. What a ripoff! I'm going back to Splitfires, they really added power and energy to the engine. With Splitfires, my engine cranked and started from "turning" the ignition switch, with the Bosch, it takes a few (too many) cranks to start. Good luck but don't dream of 30 miles to the gallon,
you might get maybe 24-26 in highway driving. Downtown driving cuts it in half.