issues. after you replaced the plenum gasket you need to obtain the use of an air compressor to perform another boost leak test. don't even bother replacing any electronic parts until you are 100% sure there are no more air leaks. BTW, if referencing the FSM I suggest you follow the steps from EF&EC 64 (High Idling after Warm-up) first and then EF & EC 67 (Unstable Idle).