my 420a engine idle problem

[0r1landoDSM]

my car idle stays high after i put the car in neutral and press on the brake slowing down to a stop light. the idle will go up to 2k and just stay there until i go to complete stop. then after i made the complete stop it goes back down to normal idle... whats causing this?

 

[Misterbeechy]

mine does that when i have the heater/ac on... sometimes.. also it happend when my Alternator was dieing but i dont want to scare you.. you will notice that the alternator is shot when the battery light stays on..

 

[0r1landoDSM]

mine does that when i have the heater/ac on... sometimes.. also it happend when my Alternator was dieing but i dont want to scare you.. you will notice that the alternator is shot when the battery light stays on..

sounds about right. started happening after i turned my heater on

 

[Misterbeechy]

yea its usually that.. also if your heater or ac is on.. you'll notice loss of power.. but yea.. its due to the heater.. leave it off after a good warm up.. it shouldnt happen too bad.. but if the car is under operating temp. then the car is made to idle high to warm the engine so dont be afraid of that either

 

[crazyboy81]

Anything heater related it's the IAC compensating for the additional load of running the compressor. So it lets in more air and the idle goes up. But it should never compensate that much. Check for vacuum leaks and possibly clean the IAC.

 

[psx]

there might be something wrong with the throttle cable
mine used to do that
check and make shure the throttle plate closes all the way
when theres no tension on it

 

[0r1landoDSM]

**** I have a new problem now since i made this thread i thought i might at well continue since my question is the same. my car started to have a performance cam idle. i had broken my pcv valve and hose and i had put a new pcv valve on my car but havent gotten around to getting the hose. i noticed a lil oil splater on valve cover and the oil dip stick was out not fully in. the car was running fine beofre then it just randomly started to have this performance cam like idle... any idea what can cause this? and what i can do to make it stop.

i just started my car up and it smelled like it was running rich but that was 2 hours of letting it sit in cold weather.