Bad idle after headlight install (WTF)

is it possible that you disturbed the MAF?

good luck.

When you removed the airbox did you mess/adust with or remove your air-flow sensor? did anything get into your meter that could be blocking the sampling tube a small piece of dirt or paper could cause a bad reading?...that's the only electrical component near the airbox so I'd start there and make sure everything there is sound..

also, are your battery connections good?...did you disconnect the battery to do the lights or knock the negative cable loose while foolin' around the driverside headlamp?.....

I'd start here and see what's up. Go back through EVERY step you made and make sure everything checks out....that usually finds and fixes the problems...otherwise I'd wonder if the problem is unrelated to the headlamp/airbox work.

well what kinda headlights? if aftermarket, it could be putting excess drain on the battery. and after reading the electrical prob with the lightsw, i would think its most likely the alt. i have one like i posted in that thread, but if you want to "solve" the prob- if it is the alt, but a alt that produces more amps then the stock, like a 150 or 170 (not sur what stock is_)

if its not that, then its either the batt or like they said. the maf