I too have an XFE, but an LS version, same year. Mine has 83k miles and it does that very rarely, but no CEL as well. Its not a huge concern to me since electronics are being used for the accelerator pedal.
If you are using other types of spark plugs other than AC Delco Iridiums (OEM), that may have affect to your hiccup. I use Nippon Denso Iridiums and have no issues so far, but once in a blue moon, it feels like my foot slipped off the pedal for a tad second. It may also have to with the cold weather.
For the shifting of 3,4, and 5, ensure you don't attempt to floor it on a very low rpm (below 1500ish), the power curve is very low on bottom end.
2009 Cobalt LS XFE U74
Mods: K&N Typhoon Intake, Option Cat-Back Exhaust, Cosmo Short shifter, Maxxim Ahead 17X7's, MPx shorty antenna, FE5 Strut/shocks, Tein S Techs, Moog endlinks, Moog spring seaters, ZZP shorty header, LSJ downpipe, LNF front grille
Last edited by 5t3alth; 12-16-2013 at 06:09 AM.