Idling too high, doesn't kick down at all

It likely has EFI (electronic fuel injection) and an idle air control valve that regulate idle speed. They can get gummed and fail to have a fast idle when cold, or get stuck the other way, and have a too fast idle all the or regularly take its time slowing down after you take your foot off the gas. An engine temp sensor can also cause a lingering high idle if it reports the engine as still being cold after warm up.

Check the operation of the coolant temp sensor.
Check the thermostat is also working properly.

I believe you have 2 different problems here. P0410 is the secondary air injection, which only turns on when the engine is cold at first start up for about 20 seconds. All it does is blow extra air into the exhaust to reduce emmisions. There are 3 fuses and items that run this system: Check Valve ($125), Air Pump ($280) and Relay ($50). Prices came from Napa, so I'm possitive you'll find any of these much cheaper elsewhere. My guess is the relay since you have dimming.

Did you recently have the battery disconnected? Trying to address the stalling while at idle. If so, it's your throttle body, needs to be cleaned. If you want instructions on how to do this yourself, let me know, will only cost you about $4. I know the dealer charges about $85 to clean this where I live, which is outrageous! If you do have a shop do the work, make them remove the throttle body to clean it, don't just clean the outside of it.

Even if you don't do this work yourself, at least you know the lingo and shouldn't be surprised.

Good luck!

this could be due to a miss adjusted fast idle screw on the carburetor. if u have a fuel inject system check the Throttle position sensor.

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

sounds real easy either a bad idle air control solenoid or more likley a blown throttle body gasket. to test fro a blown gasket, with engine running and cool spray carb cleaner or brake cleaner around base of tb were it bolts to intake. when it hits the bad area, should idle down and be normal for a second or 2. iac is possible,try this first since its so common and let me know

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

you need a new electrical choke, if you do not have one on the carbutor you can buy one and install it. it start the car right away at a high idle adjusting itself down to a low idle when the engine is warm. very cheap part. you will be very happy. no engine start to start your car.

you have 2 idle settings. one is for cold and one is for after the engine has warmed up. So find the scew that goes to the warm engine idle. turn it down and your set. You might need a Chilton to find what you are looking for.

tepfy

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.