iac keeps changing

[donZ]

why does my iac keep changing ????
i set it at 20, the next day it is at 40, then at 30, then back to 20.
ect.
everyday it has a different number, tps is at .42 and stays the same?

 

[99Formula]

Have you tried cleaning the IAC motor?

Peter

 

[TurboJim]

Originally posted by donZ
why does my iac keep changing ????
i set it at 20, the next day it is at 40, then at 30, then back to 20.
ect.
everyday it has a different number, tps is at .42 and stays the same?

Are you looking at it every time under the exact same conditions? I will vary depending on temp, load etc.

 

[tc86gn]

I have been having the same problem lately. and the idle varies from 750 to 850. in synch w/the counts from 20 to 35.I am gonna check my egr gasket in the morning. Just a hunch.
it is a brand new Iac w/ a good seal on the threads and everything is new and clean. Any other ideas or similar experiences?

 

[donZ]

not the exact same conditions, but when the car is warmed up,
after driving it awhile,

 

[salvageV6]

Vacuum leak?

 

[TurboBob]

Park-neutral switch?

A/C or Defroster on?

TB

 

[donZ]

i checked for Vacuum leak, replaced old hoses.

A/C or Defroster are off

now Park-neutral switch. i do notice sometimes that when the car is in park, that the reverise lights are on, if i push up alittle harder, the lights go off.

 

[TurboJim]

Originally posted by donZ
i checked for Vacuum leak, replaced old hoses.

A/C or Defroster are off

now Park-neutral switch. i do notice sometimes that when the car is in park, that the reverise lights are on, if i push up alittle harder, the lights go off.

That will do it, as will the cooling fan coming on, as will the charge rate dropping when the alt gets hot. SO if the conditons arent the SAME, then its kinda tough to say theres a problem.

Heck, if you set it one day, then come back in a month, just the oil schmegma that builds up in the TB will change it some.