After switching from battery to engine the car loses power and message appears "Engine not available". The Chevy dealer told me the battery in the key fob was dead, so they replaced it. It ran fine on the battery charge but, the next day it did the same thing. They offered no help and told me they had fixed the problem. I took it to another GM dealer, they told me that 2 modules needed to be updated. That did not fix the problem as I had the same results. Only this time, I stop and turn the car off and wait a minute and start the car, the engine starts and runs ok. I drove it 10 miles with no problem. So the 2nd dealer had it towed to their shop and it has been there for over a week. Any ideas??