Idle irradic when damp or cold ..starting.. have to give gas until warm,then idles ok.when warms up..idle is high and stays high.dosen't shift down.have to depress brake too much to stop..sometimes anti-lok engages...and sometimes it is ok not for very long..could be another few stops and then same problem...when tranny does downshift it hits hard..idle is not functioning properly..and it affects trans.

There is no cold start relay. Cold start mode ( open loop, rich, high idle) is controlled by the ECU. A coolant temp. sensor signals warm up to shift the ECU to closed loop mode(warm, lean, normal idle). Check the coolant sensor and correct coolant level. The thermostat controls warm up time.

Check the idle position sensor.

Possibly an idle air motor for your idle problem or a vacuum hose off.

The idle speeds software driven But vacuum leaks can raise idle speeds or weak mounts cause the shift in position giving you the jolt.

Sounds like a coolant sensor problem. It signals the ECU for open loop, cold start rich, high idle, until warm up is reached.

Check the water coolant thermostat. If it is stuck in the "open" position you are heating up all the water in the coolant system and this will take time. The thermostat keeps the water in the engine until warmed up to almost normal running temperature, only then does it allow the coolant to enter the radiator.

Hello,
The car may be hard to start because it may need a normal tune-up. If the spark plugs are pretty used, they will slowly stop burning as much fuel because the spark slowly gets lesser and lesser. On a cold day the fuel is harder to ignite with a small amount of spark.
Normal idle when its cold means that your cars idle is probably too high. If you lower the idle, the choke on a cold day will keep the idle a little higher until the motor warms and then it will kick back off. If the idle is too high, it will run very rich, smothering itself with fuel, and causing the idle to stay low. When the car warms, its creating better spark when its warm, and with the idle being too high its running at a fast idle.
The car wont start sometimes can be the cause of a few things. If the ground is bad on the fuel pump, it wont make a good connection sometimes for when you turn the key on, the fuel pump dont pump the fuel to the engine. Another one can be that your accessory switch can be loose going to the fuel pump. I think its your ground though. Good luck! Hope this helps.
Have a nice day. -Steve

If your car is fuel injection,try changing the cold start temp sender.

I need to get a clear mental picture of what exactly is happening.

With this said, you stated that the car "runs fine" until warmed up.

Q: When you start the car when cold it idles fine?
Q: If you allow the car to idle until "fully" warmed does the car stall?
Q: As the car begins to warm up, Does the RPM fluctuate abnormally?
Q: Does the car Only stall when you press on the gas pedal or does it stall just sitting and idling in addition to pressing the gas pedal?
Q: If you can drive it while cold does the car stall during acceleration when warm or only at Stop Signs / Lights?
Q: If you wait 20min or so, can you start the car again?
Q: How many miles are on the car?

The high idle is caused by the choke and the high idle on the carb. It is working normal and you do won't to warm up this motor before going. When it is warm and you hit the gas it activates the choke pull off to bring the idle to normal. Your mechanic is used to fuel injection that will control the fuel/air mix according to temp. I still let my injected cars warm up so the oil can thin a little. If you jump on the highway with cold thick oil it can all wind up in the to of the motor.