In general, vehicle is running very well. However, I notice a slight, regular hesitation when accelerating, particularly on hills. It is very consistent and seems to happen around 2500 rpm (+/- a few hundred). Every 1.5-2 seconds, the engine sound drops slightly in frequency and it feels as if the throttle drops off for a second. I don't see the tach noticeably drop down, but it feels like the engine is working, then drops a bit or encounters some resistance, working strong again, then hesitates for a second, then works strong again, etc. It's pretty subtle but I can hear it slightly and also feel the resistance for a fraction of a second.
A fair number of forum posts mention rough idle or throttle and recommend various options: cleaning the MAF sensor, throttle body, fuel filter, air filter, intake manifold, idle air control valves, etc. However, few of those posts mention the power dropping off slightly in a very regular way with a frequency of every 1-2 seconds. Might this indicate some mistiming or misfiring with the coil/plugs/wires?
It's pretty minor right now, but I just want to correct in case it becomes a bigger problem later.
Any thoughts or advice would be appreciated -- thank you & Happy Holidays!
