Yet Another RB25DET "Returning to Idle" Problem Thread

[LiteraCola]

Good morning everybody (I guess it's night time there?). So, as I vaguely mentioned in my original intro thread, my R33 S1 25t is experiencing a weird idle issue. It's not so much an idle issue as it is a "returning to idle" issue. Overall the car idles and drives just fine, no hesitation or hiccups, but when it's warm and I'm in a situation where I'm inching in traffic or backing into my garage or a parking space, upon returning to idle, the engine bogs down to almost nothing, catches itself and then idles fine. On a few occasions, the car has completely shut off on me in stop and go traffic. Also, when I blip the throttle to take off from a stop, there is a slight off-idle hesitation and this has caused me to stall out more than once. I have completely disassembled the AAC, cleaned it and reset the idle a tad higher than it was. I've thoroughly cleaned the AFM and Seafoam'd the intire intake tract. I also replaced the (probably original) spark plugs with new Iridiums with no change and I'm getting a good fire to all cylinders. Does anyone have any ideas? I drove the car to work today, so I'll go out and take a quick video in case my description of the issue was in any way unclear. Thanks!

 

EDIT: Before anyone asks, the only mods the car has are an HKS Pod and Apexi Dunk catback. The OEM BOV is still plumbed back to the intake...

Edited September 13, 2020 by LiteraCola

[hardsteppa]

Small air leak somewhere, eg a vac hose left unconnected?

[trel]

Air leak 100%. Check your lines to charcoal canister and the canister itself. I also had a leak from the boost sensor to plenum tiny little hose had split and I had exactly the issues you're having now.