we have a 95 camaro 3.4 v6 that when started up for the first time it runs rough for about 30 -45 seconds then smooths right out, we did a scan of the system and also a live data check that showed no problems this only happens during a cold start after the vehicle has been run it starts and runs fine any feed back would be great as the customer is not happy

Keeping it simple, when was the last tune up of plugs, wires, and filters?

try injector cleaner?