headlight goes out and back on - bulb?
 

my left headlight (low beam) is mostly out but sometimes comes on for periods of time (could be a day or so) and there's a flicker when I turn the lights on. Was going to replace the bulb but can it really be a faulty bulb if at times it works fine? Any ideas on what this may be are appreciated. thx
2008 gen1

Do Gen 1s have HIDs? (I have a 6)
If so, change the bulbs first (both sides). If it's still acting up, the connector or the ballast is the next suspect.

they are HIDs. I am not used to the bulbs sporadically working - always thought they either work or they don't but I guess I was wrong. I'll start with replacing the bulbs, thx

Also check the connectors for dust/rust, spray some contact cleaner if they're dirty.

If you have an ‘08 Sport, it’s halogen, if it is a GT, low beams are HID xenon. Intermittent outage usually means plug/socket/connection corrosion. Clean and apply dielectric grease to the contacts to keep moisture out.

If they are HID, check connections to the ballast and to the bulb.

If all that checks out then It's probably the ballast or bulb is failing. What you can do is swap the left and right bulbs and see if the problem moves to the other headlight.

HIDs work by sending an electric arc between two electrodes. For whatever reason the system can't start or maintain that arc it will shut off.