this is my 1993 efini rx7
i installed a rebuilt short block from rx7 specialists in calgary and i already put over 700km and havent had a single problem, but yesterday i boosted a little more than usual and it felt fine but soon as i went into neutral it would rev to 1800-2000rpm then down to 1100-1300 then once i was almost compleatly stopped at a ligh it would sit at 1200rpm.
i took the upper intake off and tried to look for a loose line but couldnt find a thing, i took the sequential solinoid off and there wasnt anything loose underneith that either. i have know idea what it could be i tried it again this morning and it was still the same, so i took a video.
please someone tell me what could be causing this or where it is coming from
sorry for it being on iphone so its sideways, n iphone so its sideways,

 

Not quite sure, but try unplugging it and letting the car run for a while to see if it goes away. Sounds like it might be having trouble handling the boost, so it lets some of it escape, then it pressurizes again. Let me know if this works.