1985stang

Is it normal for the idle to drop VERY low (sometimes down to 200-400 before i would hit the gas to bring it up again)when humid out ona carburetor. It makes driving in rain and snow rather challenging when you add the problem of having to stay on the gas or it will die. I know carburetors aren't the best when it comes to atmospheric changes, but i'm sure people got along just fine a couple years ago when carbs were the only things on cars (no EFI).

boof1027

Factory or aftermarket carb?

1985stang

Factory carb. I actually went to a local parts shop, and I think moisture is getting into the distributor cap. The MSD cap has a little vent thingy that is probably letting in moisture so i'm gonna seal that and see if it helps. Any other ideas? Thanks for the reply btw.

Derf00

sticky carb float valve might cause that. Smell fuel when it wants to drop the idle? Could be dumping too much fuel causing the engine to bog.

What makes you think it's moisture in the cap? Getting arc marks in the cap or pitting on the rotor nose?

Jfsram

This is common for a carbureted vehicle when it's damp out.

The intake manifold is cold and the fuel/air mixture is too lean for this condition. The cold intake makes the fuel drop out of suspension.
Cures from the factory are a richer mixture via choke during warm up. Heating the intake with a crossover and blocking the air with a choke flap to richen the mixture.

Put up with it because chokes are more trouble than help.