Rough Idle (video)

[a.p.barron]

So my Z has been idling pretty rough for a while now, and I haven't been able to figure it out. I've even taken it to 2 different Z specialists, and they said it wasn't a big deal, and it's probably due to the car's age. They were able to figure out that my IACV, timing, and TPS sensor weren't to spec, so they took care of that. They also told me that my car is running very lean. Here's what I've done so far:

- Checked for codes, I'm getting a 55
- Checked the o2 sensors
- Replaced a faulty injector
- Inspected all the vacuum lines for vacuum leaks
- Cleaned a bunch of sensors and connectors, specifically the injector connectors, coilpack connectors, TPS, CAS, PTU, and EGR Solenoid
- Cleaned the MAF and MAF sensor

Anything else I should check?

Any help would greatly be appreciated. This is driving me crazy!

Here's a short video of the idle. It's best heard with headphones on:

http://www.youtube.com/watch?v=ZSBPwv4BWOU

[t.mcginley.jr]

How old are your PCV valves and/or hoses?

[t.mcginley.jr]

Oh and how old are you spark plugs? are they OEM?

[a.p.barron]

The PCV valves/hoses were replaced 32k miles ago, but this issue started well before then. Still, think they might be clogged? The spark plugs are Denso iridiums, and were replaced a little over 2k miles ago.

[t.mcginley.jr]

The PCV's are usually good for 60k assuming you put OEM ones on. Most people who try putting OE ones (made by other companies) usually cause issues on this car for whatever reason.

I'm assuming you have stock fuel injectors (with a square connector, not oval). Have you verified that the other 5 aren't bad?

[a.p.barron]

The PCV valves are for sure OEM. I do have the stock old style injectors. I ohm tested them about 3 weeks ago, and they were all well within spec, except for one, which was at 15.3 Ohms. That one got replaced. I know they should all be replaced at the same time, but if I were to replace all of them, I would change them to new style injectors and grab the adapter. Needless to say, that's hella expensive. :-\

[t.mcginley.jr]

From the video it doesn't seem to be that rough, just a little bouncy. What exactly did the "z specialists" do to the IACV? Did the take it off and clean it out with TB cleaner and then lube it with wd-40? Or just test it with a multimeter?

[a.p.barron]

He mentioned something about resetting it back to factory spec. He said the value is supposed to be at 15, but mine was at 38. Not sure exactly what he did, but I'm guessing he plugged in his consult and adjusted it from there.