It can drop on any.
I still don't think it's a seat issue. It wouldn't run lean on that cylinder anyway, it would run rich.
I would be looking for an intake manifold leak if it's on a single cylinder. of course, just because it only has the code for one cylinder doesnt mean it's the only one.
For the record, mine would randomly run like crap no matter if it was warm or cold. During warmup enrichment, there's quite a bit of extra fuel (hence the enrichment). Enough that it may not make a small leak noticeable.
Time to grab a can of carb cleaner or something similar and spray around the intake manifold. (and any other vacuum source for that matter).