SERVICE ENGINE SOON light led the dealer to replace the emiissions system Purge Valve. The next day when I started the Envoy I could smell gas comming from the dash vents and outside the car. I returned to the dealer and they replaced the gas cap, a good guess but the problem persists. I returned to the dealer and they could find nothing wrong. This problem happens on cold start-up with full or partial gas tank capacity. Any ideas?
