Rough idle while warming up, goes away after a tiny rev

Question

I have an 84 Ranger 2.8L V6. It seem that nearly every time I start the car, it has a pretty rough idle while it warms up. If I just rev the engine a little bit for a second and release (just barely tapping the pedal once), the idle smooths out instantly, even if the engine is still very cold. Is this a normal part of the autochoke mechanism or something? Shouldn't it wait until it's "warmed up"? And is this something that I can adjust?

Answer 1

You have two separate idle settings on your carburetor.

One is for the choke idle and the other is for your off-choke idle.

When you start your vehicle in the morning the idle setting will be fixed on the last termperature of your vehicle, so if you drove home the night before and the engine was at full operating temperature you would have that idle setting in the morning.

When you start the car the idle would be set lower and it would run a bit rougher due to a lean condition based upon the viscosity of the fuel and other variables.

When you blip your throttle, the fast idle is able to get passed a detente in the variable idle and notch up to the full choked idle of the vehicle, hence it runs better.

What you can do.

Blip your throttle when you get in the vehicle in the morning to reset your idle. THEN start it. The idle setting should be set for a choke setting and the idle should be normal. Once the engine warms up you can blip your throttle again to notch down the idle setting.