Ok I ordered a chipped p28 for my h22a the car has been running aP30 which came with the car when I plugged in the p28 and started car now I have a pulsating idle when I put p30 bk in car runs fine any ideas of the reason for that

 

use the p30

 

I don't want the p30 the p28 is tuned specifically how I want n it wss done by a professional I want to know y it causes the idle issue