Hey so did your Z ended up relearning the idle?

 

I'm having the same issue, I got my car about a year ago and I've always noticed that only when starting the engine when it's already warm the rpm will dip very low, like sub 500 rpm and seem like it almost stalls, and then raise right back up as if nothing happened. Like I said, it's been going on for as long as I've had the car, and I've tried to clean the MAF and throttle body, and I've changed just about every fluid in the car, air filters, oil/ filter, spark plugs, and got a new battery, it isn't a serious issue or anything, but it's something odd I've noticed.

 

So I got my 07 HR with close to 75,000 miles, eversince the beginning of this year it started to do this randomly, I had the MAFs , Throthels cleaned, took it to the dealer for a stock flash but no every time its warm is just stalls if I don't give it gas. A near by friend said he "fixed" his by changing one of the relays behind the battery. any advise. oh by the way mines I got the JWT pop chargers, Z1 HFCs, and Borla Exhaust, no UpreV yet. Help is appreciated

 

Do a live data scan of your coolant temperature sensor and your manifold absolute pressure (MAP) sensor. Also check your fuel/air mixture and make sure you're not running too rich or lean. Make sure the sensors are sending data within spec from a cold start until it idles at normal temps. If the data reads are good, then start checking for vacuum leaks.

 

Not sure if the car will always fix itself.. I have a 2008 and my car has been doing this for at least a year now. It's fairly rare.. only does it on maybe 1 out of 6 warm starts or so and often it will start to die and I'll rev it up and keep it alive.. I'd love to know how to fix it tho!

 

However, every warm start the idle dips a little further than I feel it should... Of course cold starts this isn't a problem at all..