20v ae86 won't run right on damp mornings, help!!!!

ok here i go... i just put in a silvertop in my ae86, it runs really well and i love it, however, on a couple of damp mornings i've had trouble getting the engine to run right, it would barely start and then idle very low, bog out when i step on the gas while in idle, and even choke out and stall... i'm completely puzzled..

all the wiring has been checked, nothing is getting wet, ecu, ignitor, coil, etc..

later in the day the car runs fine, when the weather is hot in the morning the car runs fine..

the car did this once with my old 16v.. so i'm thinking fuel filter or pump, but that would mean i should have a problem all the time, i don't, the car runs amazingly always except in the above scenario..

HELP!!!!!!!!!!!!