fully extended would be trying to slow idle down sounds like you have a vacuum leak

 

snowbound -- did you disconnect the battery before sensor install? Any sensor replacement needs to be preceded with a battery DC to reset. Vac leak is good suggestion to rule out.

 

No I never thought of unhooking the battery. So next time unhook it, replace sensor, and then hook it back up? I don't think it's a vacuum leak because with the old sensor it required my foot on the gas to keep it running after Erving it up and the idle was really low and rough.

 

If you didn't reset the PCM when you changed the IAC, the PCM still thinks the old one is in there, and is basing its calibration on that.... which is gonna be wrong.

Try disconnecting battery, turn on headlights, turn off headlights, reconnect battery, turn key to "on" (not start), count to ten, THEN start the engine. See what happens.

 

Ok thanks for the tips guys. I'll give it a try.

Edit- Since my engine is cammed is it possible I may need to do this or is it a bad idea to mess with it? http://www.bionicdodge.com/Download/...a%20Magnum.pdf

 

If things are working the way they are supposed to, that shouldn't be necessary. That set screw is supposed to used to set minimum idle speed. (assuming IAC valve is completely closed....) You *could* use that to raise minimum idle, but, a better way to do it would be changing the parameter in the programming. (and changing the programming won't have the PCM whining about not be able to reach target idle.)

What cam do you have in there? Real possibility that the 650-700 RPM target idle for a stock engine is simply too low for that cam.

 

Here's the cam: http://m.summitracing.com/parts/cca-20-604-9
.512 lift
112 lobe separation
210 intake 220 exhaust duration

 

^^^ Same cam same problem.

https://dodgeforum.com/forum/1120748-post60.html

 

So I need more vacuum then right? I'll have to look into adding a vacuum canister like him. I also read I can plug the vacuum port for the map sensor in the throttle body and run a line off the intake for it to give it a better reading. I got it from bionic dodge it reads-
Plug the MAP port on the throttle body and relocate the MAP line to manifold vacuum (should be about 12-13" at idle). This will simulate the factory signal and your idle quality will be back to normal. There is no adverse affect on the cruise or WOT performance with this modification.

 

Got a new iac and reset the computer. It doesn't idle high now but it's back to it's bogging down if I take my foot off the gas after revving it. I bought a vacuum gauge and it makes 12-18" of vacuum. I think I need set the throttle plate angle. The iac also doesn't retract at all when I turn the key on like my Haynes book says it should. I should probally start a thread or move this over to my engine build thread haha. I was expecting to fix this by now.