I have a 2006 Grand Prix and every now and then it just quits running. Display says it's the ETC and engine lost power. I'll sit for a minute and it restarts. Went and had it hooked up to see if it showed problem codes and nothing came up. I need help... Thanks.

Reduced engine power light comes on if you have a bad mass air flow sensor. Check for a bad connection, if it looks secure, new sensors are pretty cheap at Autozone.. Sometimes oil change places will unhook it for for a variety of reasons.

The ETC is designed to reduce engine power when the coolant temperature is out of range. It's not supposed to shut the engine down however. The fact that it resets by itself tells me that the ETC is sending too high or too low a voltage signal and it's triggering the Powetrain Control Module (PCM) to black out. You may or may not see an OBD trouble code in this case, but I'm surprised you're not seeing a P0118 code. Have your shop check the voltage coming off the ETC sensor(s) and check the wiring harness and connections for voltage losses. It's supposed to have a 5 volt reference coming off the PCM, and a standard ground. Sometimes it's as simple as cleaning the connectors, but if you need to replace the ETC sensor it's an easy fix.