hesitation in engine/cold air intake installation

ok im drivin a '97 golf 4 door 2.0 sapositly durin my 30 warrenty the dealership fixed this hesitation..or missfire in cylinder 3... an like 3 days after it was up it started missfireing again...any ideas as what i should do to fix this problem my self?

also i've purchased a cold air intake...i've been waiting for time off from work to install it yet no directions came with the intake...its prolly a brainless thing to do..however its my first upgrade to any vehicle i've owned...so suggestions are welcome..

Is it still only missing on #3, a dead miss at idle or a random sputter? Run by Autozone or Advance Auto & have them scan it (usually for free) to be sure it's not a random or multiple cylinder misfire. If it's only #3 then see what the dealer did & go from there. It could only be plug wire, cap, injector or low compression.

^^^dealer is goin to fix thee problem free of charge due to the problem still being under warranty an not being fixed..now on to the intake thing