2005 aveo, check engine light And "Hold" light flashing...

[azaveo]

Hey,
i have a 2005 aveo that is giving me issues. the check engine light is flashing (p0300, random misfire. i checked/cleaned/regaped the plugs) check the wires and connections, everything looks good, no vacuum leaks that i see, egr seems ok), and i also at the same time have the "Hold" light flashing, and when it does so...the tranny will not shift into 4th gear, it just stays in 3rd. however when the hold light doesn't flash the tranny shifts smooth and fine into 4th.

this is my first aveo....any idea's?