First off, I have a 94 camaro 3.4l 5spd. It had an interior fire and I replaced just about everything in the interior. That includes the interior wiring harness. Everything works with the exception of the data link. A stock harness was used and I don't see any reason why there would be any issue there (although I haven't ruled it out). I'm pretty sure the pcm should be throwing a code or two, the AIR pump is dead and the EGR valve isn't working right. The fire was an electrical fire under the driver side dash. The car runs fine so I'm thinking... could a short during the fire have fried the datalink connection in the pcm? Kind of like when a computer's modem gets fried in a storm that pci port won't work.