I saw others with this issue but can't find it anymore. I have a 2008 Ridgeline with 130,000 miles on it (I've been the only owner). I also have the surge issue, it started about 6 months ago (summer 2014). When I am driving at exactly 45 MPH between +/-1200 and +/-1500 RPM on theTACH the engine surges. I think it is more apparent if going up a grade. If I keep it there I will hear what sounds like a flutter or blow-by noise. At 43 MPH nothing, at 47 MPH nothing only at 45 MPH does this happen. I am not sure if I would tie it to the TACH RPM because it varies and is not at one (1) constant TACH RPM when it happens. I was thinking the surging could be related to a computer chip about to go into failure mode.