mazdaspeed 6 inconsistent idle but no vaccum leaks

[Matt Dickey]

so my dads speed 6 idle varies between 950-1150 sometimes in between and we cant find any vaccum or intake leaks that would cause this so were trying to figure out what sensors may be responsible before we just start throwing parts at it. if it matters the mods are hpfp internals catless dp and race pipe, BNR s3 turbo egr delete vtcs delete CS 72mm throttle body and 3" corksport intake, cs tmic 3.5 bar map sensor grimmspeed 3 port boost controller

 

[Matt Dickey]

@Enki

 

[Enki]

Running an aftermarket (larger) throttle body with a tune for it is likely the cause. Unless it's tuned *just* right, it won't behave like stock.
The upgraded tbody is unnecessary unless you're shooting for 600 or more WHP, I'd say. Whoever tuned for that throttle body needs to retune it or you need to swap a stock one back on the car and remove the throttle tune.

Edit: It could also potentially be PCV check valves sticking/opening at weird times or some other esoteric issue, but I don't see anything really wrong in the logs.