'Rough' idle when cold/hot ...?

2000 JAGUAR XJ8
35,700 MILES
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MCM
  • MEMBER
  • 4 POSTS
2008 XJ8, with 36,300 miles --

18mpg around town; 21.5-22mpg on open road @ 70-75mph
air filter recently replaced
Sep 28, 2011 at 6:26 AM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
if it truly is a rough idle, then try cleaning the throttle plate with choke cleaner on both sides with engien off. it willstart hard after doing this. make sure to reconnect all duct work before starting the car and clean teh iac valve hole as well. if the service engine light is on get the engine scanned to see why as that may be the casue of your rought idle as well. Also getyour fuel pressure checked.
Sep 28, 2011 at 7:48 AM
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