stabilitrax and traction control service lights with check engine light flashing

I have a 2007 GMC Yukon XL...I was driving down the highway and heard what sounded like a spring being sprung....then there was a thumping..the traction control and stabilizer service lights came on with the check engine light flashing....I got off the highway...It was a hard acceleration with some clunks but once moving the vehicle was fine...I had no loss of power, no missing, no overheating, no lose of mileage...I drove it to the mechanic who said I need a new engine...that is was only running on 7 cylinders and that was causing an imbalance making the stabilizer and traction control lights to come on and it needed a new engine...is this possible?