i was sitting at a stop sign the other day and i noticed my idle went real low (i have digital dash and only had 2 lines above 0 so it was less then 500 rpms) i shifted to neutral and it went up. i got the car home and thought it was my IAC. i took it all apart, got it out the tip was black with carbon. a little throttle body cleaner on a rag later it was all cleaned up. i got it all back together, it still idles low, i would turn the idle stop screw to bring the idle up to about 800 in park but back down to like 500 in drive. if i shut the engine off and restart it the engine runs at over 1000 rpm (like 1200) the only way to idle it back down again is to turn back the idle stop screw.

 

the idle stop screw is used to set the minimum idle speed with the iac commanded in. It is the iac's job to control the engines vacum to raise the throttle in neutral and park, cold start and decel.

 

is my iac bad then?

 

it could be bad. its obviously working some.

http://chevythunder.com/do_it_yourse...ation_page.htm

 

i dont understand setting the minimum speed cause if you extend the iac to close off air bypass how is the engine even gonna run?

 

when the iac is fully extended that is the lowest the iac can control. he air entering the engine at that point would be through the slightly opened throttle blades.

 

ok i went out and got this multimeter to test my TPS also, but im kinda confused will this one work for my application? what setting do i put it on to test it?there is alot of settings on here i dont understand. little help?

 

bump...

 

it will work put it just like the picture vdc