ok the car is a 94 civic with h22a swapped into it.

the problem is at idle a cold idle its been running around 15.5 to 1 afr's.
when cruising its been running around 14.7 to 15.0 afr which is fine.

but sometimes at idle it will slowly start to lean out to 16.0 to 1 and then it will missfire and start the process all over. and on a hot day the afr sometimes will dip down into the mid 13's on the afr gauge sitting still idling(completely warmed up)

so im thinking it has to have to do with the fuel system.

it has stock injectors stock filter and a 190lph walboro in-tank pump.
i replaced the fuel filter and it didnt help
could a injector be clogged?
pump going bad?

by the way it is running the stock ecu, and throwing 2 codes one for the egr (because its not there) and one for the o2 heater( i have a plx wideband in it and went by their instructions it will throw a o2 heater code but not affect anything)