idle problem

[Tweakin TE]

hi guys. last night i was sitting at the lights. the gem, when i'm at lights or stopeed in traffic, when i wait long enough, the engine sorta shudders then comes good again, it only lasts for like a second. last night it did it, came good, waited a bit longer for the lights to go green, and it shuddered and stalled. could it be starving for fuel? the float window is just above the level line, and it's not flooding caus it's running lean as *we tested emissions on the dyno at tafe a few days ago* maybe a blocked fuel line to the carb? my teacher said for me to drill out the jets a little, but i'll fuck that up, so any suggestions on what it might be?

oh yeah, it's an auto as well, which makes it even worse
thanks, andrew