My Wife's 2002 Accord EX I4 with At with 220k. All mantience has been done at the dealer. Today during hard acceleration the car started sputtering between 3500- 4000 rpm. The tach was bouncing back and forth between those numbers and the car kinda jerking along. Let off the acclerator it goes way and runs fine. Get back on it and it does it again, when it reaches 4000 rpm. It is due for a service next week. Any ideas?