2000 Audi A6 Avant Quattro Wagon C5 needs work

You are bidding on a used 2000 Audi A6 Avant Quattro wagon (C5 model) with 186192 miles on the odometer. This car has been a very liable commuter for 10 years. It was garaged for most of its life and has had much maintenance done recently. Currently it does not run right. It has misfires in all cylinders after a few minutes of driving then it drives normally for a while and has occasional misfires in 5 out of 6 cylinders. I replaced the PCV valve and ducting but that did not help. I need a reliable commuter and I have no time to chase down this gremlin. If you have experience with the AUDI 2.8 ATQ engine then you may know what to check next.
Recent work:10/15: cleaned oil pan and installed new oil pump $3008/15; New A/C compressor and battery $4502/15: repaired center display on dashboard $3009/14: New exhaust from cat back $12006/13: new front upper and lower suspension control arms installed. $6503/12: new catalytic converters on both banks and all 4 O2 sensors replaced $2100

The timing belt was replaced at the Audi dealer in Huntington, Y at 109K miles. The miles are mostly highway between NY and Florida until 2010. Oil changes were done with synthetic 5W30 every 5K miles. There are many cosmetic issues as you can see in the pictures: crack in the windshield on the passenger side, crapes on the sides, ent in the c-pillar on passenger side, ip in the rear seat leather, he outside mirror adjusting knob is damaged but still works. The car has all its manuals with radio code and two keys.
This is most likely an easy fix for someone who knows the 2.8 ATQ engine and its problems or it is a great parts car. The exhaust and catalytic converters alone cost $3300 and can be used again.Sold as is, o refunds or returns. Please ask all question before you bid. Buyer is responsible for all shipping arrangements and costs. This car can be driven but misfires. I am willing to deliver locally (25 mile radius) for the cost of gas and tolls.