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Matt, Mechanical Engineer
Category: Jaguar
Satisfied Customers: 22737
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a ***** *****ght on my Jaguar XJ8 (1999 15 years old) it

Customer Question

I have a ***** *****ght on my Jaguar XJ8 (1999 15 years old) it says reduced performance. I took it to a back street garage who did my MOT and he charged me for 2hrs work and a diagnostic check altogether £100 but as its an intermittent fault he can only tie it down to possibly a Lamda problem around the catalytic converters or even a fuse or bad earth. Without a wiring diagram he can't trace this problem through. What do you think and would I be better to take the car to a Jaguar garage and pay their charge instead of buying a wiring diagram and using the same garage to see what he can do. I bought the car in June and apart from this problem its been great and runs well. The car as you can imagine was a good deal for this age of car.
Submitted: 3 years ago.
Category: Jaguar
Expert:  Shantal-Mod replied 3 years ago.
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Expert:  Matt replied 3 years ago.

when you get the 'reduced performance' message then its usually a problem with one of the major sensors like;

MAF meter
Exhaust O2 sensors
Throttle position sensor
Cam position sensor
crank position sensor

as the fault is intermittant and the message isn't permantly on I'd say a Jaguar dealership won't have much more luck with a diagnostic test

their equipment is better however as it can monitor all sensor values to see if the range of measurement is within specificiation

What I'd suggest is to locate Jaguar specilaist in your area

as they tend to have the specialist tools and knowledge of a dealer but at a much reduced labour rate

if you can let me know your wherabouts I'll try to reccommend one for you