Check engine light came on. Power was restricted. Engine now running rough.

SOURCE: 2001 Jaguar XJ8 Idles rough while sitting

o2 sensors often cause a rough idle at stand still. Previously my xj8 had crank case ventilation (pvc valve essentially) issues that caused the check engine w/ restricted performance. I noticed a severe drop in gas mileage as well. Jaguar dealer fixed my problems in a few hours and it was surprisingly cheap. Its worth taking it to advanced or auto zone to see what the computer says. Then decide if you want to shell out for a dealer fix or if you can tackle it yourself. BTW, just to justify myself this is my third jaguar. I have a '94 xj6 with a chevy 350 inside it, previously owned a 95 XJ6 and currently have the xj8. They are wonderful cars if you can put up with their rough times.

SOURCE: check engine light is on,display says restricted performance

Anything can cause the check engine light to go on from a loose gas cap, to a transmission issue. When the onboard computer detects an issue, it will restrict performance so as to not damage the engine any further. An Oil change won't affect this light. The only way to determine the cause of the light is to have the computer scanned with an OBD-II tool (Autozone does this for free) to determine the codes and cause for the light. You can also clear the light with the OBD-II tool, but if the problem is still there, the light will just come back on

SOURCE: 2003 Jaguar S Type R 4.2L SC. Check engine light

Rent a scanner, read out any code(s), and pursue to repairs. It may be as simple as bad spark plugs and wiring, or worse, fuel problems from the injectors back to the fuel tank. A worn O2 sensor can cause improper fuel/air problems.

SOURCE: have a 2000 jaguar s

You have an exposed electrical source and/or a fan belt that is slipping when it get wets. When the belt slips, voltage drops and ignition is very voltage sensitive. Check you fan belt if it seems loose and or glazed (smooth)

Raygin

• 322 Answers
• Posted on Apr 28, 2011

SOURCE: My 2005 Jag S-Type 6

You have a fault condition in the the engine management system - get the codes read to indicate where the fault lies ... It is probably just a faulty sensor as this is the most common cause of check engine warnings. The restricted performance condition is meant to protect the engine or components from damage, so don't panic - get the codes read - its probably not as bad as you expect. hope this helps - good luck.