" HELP NEEDED" Check engine lamp is on

The check engine light came on about 2 months ago on my wifes car. It's a 97 GRAND AM GT with 3.1 and auto trans. I had the auto zone in town scan the ECM for codes and they came up with evap system( code 42 if recall). The "counter help/auto technician" advised buying new gas cap. 20 dollars lighter and no fix. Next I took the car to a repair shop for some unrelated repairs and mentioned the problem. He scaned and came up with same code and suggested EVAP SENSOR bad. He cleared the codes and everything was fine until last week. Lights back on and I'm stumped!!
Am I going in the right direction?

Any help available would be greatly appreciated.!!

Welcome to AF!!

The problem could be totally unrelated to the original problem. Take it back to autozone and get it scanned again. Make sure to write the full code down and repost it here and someone will help you with the issue.

Thanx GTP DAD I will this evening and I'll repost with a trouble code!!