One problem related to gas recirculation valve (egr valve) has been reported for the 2011 Ford Fiesta. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2011 Ford Fiesta based on all problems reported for the 2011 Fiesta.
While parked with the vehicle running (about 30 minutes in 87 degree weather with the ac on), the transmission felt like it tried to go into drive and rocked forward slightly. I looked at the dash and the check engine light came on. I tested the vehicle and it seemed road worthy enough to try and get home. When driving home and stopped at a stop light, the car's display for park, neutral, reverse, drive, started quickly flashing between drive and park. I could not accelerate the vehicle while this was going on. I placed the vehicle in park, and then met fairly heavy resistance putting it back into drive. After a few seconds of flashing between drive and park, it stopped and I was able to drive again. The same thing happened a few minutes later while I was about to turn into the Ford dealership. This time I tried turning off the vehicle to see if that would remedy the issue. I was unable to start the vehicle for a minute or two after because it was acting as if I was in drive (or the fast park / drive flutter) and trying to start it. It's been two days, yet I haven't heard back from the dealership on what this problem is. I did receive a recall notice that spells out the exact symptoms that I had, yet the mechanic has twice said it is very unlikely that the recall part, the tcm or transmission control module (which is back ordered six weeks), is the actual problem.