Help diagnose idling issue

[jetice]

This has been intermittently happening for a couple of weeks now, and it only happens when it is in closed loop. I have ruled out vac leaks, and by what I have read, it doesn't sound like an IAC valve. Anybody have any ideas?

[Gaspo]

my 94 z28 did that. it was a coolant temp sensor. made it run rich at idle and not want to start. at idle it would rev up and down.

[2002Z4CSS]

I fthere are no vacuum leaks, get a scanner on it and check all of the input data to the ECM. Assuming there is no check engine light on.

[jetice]

Thanks guys, I was trying to find the issue this weekend, but kept having things pop up. And to add to the closed loop idle issue, my car started to miss while out on woodward friday night, and I have a good idea as to what it may be Hopefully I can get enough time this weekend to get both of these items fixed.

[Darren]

Hopefully the new issues isnt the OPTI fail...

[killa89trans]

coolant temp sensor/ IAC valve could be stuck open/close

[jetice]

Has anyone herd of the Delteq opti-delete ignition? $362 plus a Northstar ignition module and coil pack. Seems like a nice option besides the opti.

[Nocooler]

The delteq looks similar to the opti delete Bob Bailey created LTCC http://www.bailey-eng.com/LTCC.html

Bob's stuff is normally top notch - but it might be a little more expensive.

[jetice]

Yea, I like the idea that it uses ls coils, but in that lies an issue. Every junkyard I have been to knows what the coils are worth and try to get every penny they can for them. Whereas with a N* coil pack , I would bet that they almost give them away. I will price them both out and see which one is cheaper.