I am running AEM Infinity with an SOS supercharger setup.

I am having an issue with my cold idle. For the first 10 minutes, the idle is rough even though RPMs are steady. The car stutters while driving around with lean spikes and the car jerks around a bit. When the car is warmed up, ~ 5 minute after reaching 3 bars, idle is back to normal and car drives fine.

I don't think it's the tune because it worked well last season and I reloaded my map, tried an older map, etc. and still have the same problem.

I tried cleaning the IACV and it seemed to helped but the problem is still there this morning. I started the car up for 5 minutes and idle was rough. Took a break for breakfast and came back to start it up and its smooth again.I am reading it may be a blown head gasket. Any thoughts on what I should try to diagnose the issue before tearing the engine apart?

 

Wouldn't lean spikes indicate a vacuum leak? If your head gasket is leaking, then you'd have poor compression/combustion and have rich spikes. It may be the tune, if it's happening in the first 10 minutes the O2 sensor isn't even doing anything, car is still running in open loop.

 

I don't know how a vacuum leak gets better when engine is warm. I confirmed the idle is actually close loop. It is actually right around 14-15 AFR so air fuel ratio.

 

Maybe heat making things expand has something to do with it.

 

I tried disabling an injector/ignition on one cylidner in the AEM infinity and the engine has the same rough idle feeling (misfire). Car sounds like a WRX. I ordered some coil packs to see if it will fix the problem.

 

If cool packs don't fix it, try your injectors. Me and a handful of other folks have had strange cold idle issues that were traced back to the injectors. It does not seem like a super common issue but it does happen.

 

Update on this. I got the new coil packs on Friday and it has not been misfiring since. Hopefully it stays that way! The coils also affected my idle a bit and i had to change a couple parameters in Infinity.

 

Still had the issues a few days later. Guess what it is?
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Injector pnp adapters! When I touched it the clip it stopped misfiring. And what's even more crazy!? 3 out of my 4 pnp clips had the issue when I gave the connector a slight bend (still clipped).

Lesson learned. The Honda side of the connector on these pnp adapters suck. I have a friend that recently just had the same issue with his as well.