Restricted performance light

[Graythepilot@aol.com]

Me again!
Getting too often, suppose I should get a B.M.W. Ha! just kidding.

I have a problem, yesterday after a fortnights hibernation, (snow) the car had a small misfire then after about an hour the 'restricted performance light came on.
Questions,
1. I suspect a plug, anyone agree?
2. Any pitfalls in changing them, £2 million pounds worth of special tools, degree, its easy exept for the front suspension removal etc ?
3. can I use the car, to get some plugs?

Thanks fellow jag men.
Gray

[joejag308]

Lots of different things can cause a misfire.......plugs leads, plugs, valve sticking all sorts of things but if it seems to be a plug thenits not too damaging to go and buy some plugs and install them.......if that doesnt work try new leads.........its a process of elimination ........but you can call in at your friendly Jaguar Specialist and put it on his diagnostic machine then you will find out exactly what the problem is without buying parts for evermore............Joe

[J44EAG]

Take a look at my V8 "coughs and splutters" article on page 44 of the March 2009 JEC magazine. This will give you some leads on the problem.

Spark plugs with more than about 50k miles use have a tendancy to begin to break down. Throttle bodies and MAF sensors also need a good clean out now and again. Crank case breather residue bakes into a sludge and gums up the works. Five minute job with switch cleaner for the MAF: a further twenty minutes for the throttle body using spray carb cleaner, rag and a tooth brush. Wear rubber gloves, the gunge is hard to remove from bare skin.

I believe there was a throttle body recall on XJ8`s at one time. I think that was something to do with stalling under deceleration. Perhaps Joe knows something about that?

Mike

[BrianG]

Joe,

I know you always claim to be non-technical, but really, even you should know that our XJ8s do NOT have plug leads! They have the coil-over-plug system which has been around since the introduction of the X300 version of the XJ6.

[joejag308]

Brian really i did not know.how to put it..........i dont mess under the bonnet too much these days only to to check levels and clean.........i have all my work done by my Jaguar Specialistr. I do have knowledge from years ago plus a general knowledge of vehicle basics.
If im not sure and say the wrong thing i do appologise and i do respect anyone with superior knowledge.
I get mxed up with "days of yore " mechanics and the modern way of going on.......but if you do want any info on cars with leads give me a shout........ha ha .......joe