Jaguar Repair Question

1998 Jaguar XK-8 mileage: 76,000. Hi, I own a 1998 Jaguar XK-8 it has been a great car for years but now when I take my car out first thing in the morning it runs rough, seems low on power and sometimes backfires. When it warms up it seems ok. I have had all regular service work done at the dealer so I took it in. They charged me $122.00 to tell me they didn't know what was wrong. They scanned the computer but it didn't show anything and they couldn't get the car to duplicate it. What do I do now?

I would treat this symptom, the same as ''Cold start Difficulties''
http://www.automotiveforums.com/vbulletin/showthread.php?t=968532

Suspect - A bad MAF sensor, or a dirty throttle body.

76kmiles/11years old = 7k miles a year.

I would try cleaning the throttle body, and clean MAF/IACT with some CRC MAF sensor cleaner.

Caution - Throttle plate cleaning on a Drive-by-wire system, see Troubleshoot Jag P1589
http://www.automotiveforums.com/vbulletin/showthread.php?t=968873