96 buick lesabre

Hi
I have currently two issues with my "96" buick lesabre custom. This has a 3.8 under the hood .
First of all when the weather gets a bit cooler (as now as I live in N.E.) the throttle is high at start and will not always go back down...terrible on my brakes. Please note that when I come to a stop and wait 5 seconds or so the throttle will drop back to normal, but depending on factors such as engine temp or air temp I may have to put up with this for some time. I am looking for any info on where to start on this problem.
Next problem is also connected to engine temp. If I find myself idling too long or stuck in traffic the fan will start to run (normal right) but my rpms will sky-rocket ????
Looking for help with either or both of these issues, they may very well be related. By the way, I changed out the IAC thinking that may be sticky and thus the slow idle return on cool morning...no affect.

thanks hope to hear something....Dodger

 

I might try to remove the iac and clean the whole throttle body and plate with carb clean. I also use steel wool in the iac bore to make sure it has no burs and the iac seats well. The fan is problably normal.

 

You might have a faulty temp sender that is not giving the computer correct info. RW