I don't feel it in the gas pedal, but I rev the engine manually via the throttle plate, I can feel it through the plate. When you check the other cars, lift the hoods and rev the engine up to 2k rpms real quick repeatedly... this is when you can really hear the knock come in. For me, it sounds like it's coming from behind/under the valve cover... but a noise like that is hard to pin point. I've noticed it since around 100,000 miles, but that isnt to say it's done it since I've owned the car. My engine now has 161,000 and still runs fine so it can't be anything serious. I forgot to mention that both the 92 Civic LX and 90 CRX that my friends own have it too, to a lesser extent.