One more Accord thing - misfiring under part throttle (?)

[Secret Chimp]

I'm not quite sure what this is, but I've found that sometimes if I coast at relatively high speed - say 40+ mph - and just slightly step on the gas, enough to keep the engine from braking, I'll feel the car make a bunch of somewhat intermittent, quick little jerks. This seems to happen downhill or when the engine isn't under load. It feels as if the engine would make that "pooom pooom puh puh poom puh poom poom puh pooom" kind of sputtering-popping sound if I had a fart can on the thing.
This car has 166,000 miles on it and was run through some warranty-certifing garage that fixed a ball joint and pointed out a motor mount that needs to be replaced soon, but apparently they skipped basic check-up/tune-up stuff. I had to replace the air filter, I think the transmission could use a change/flush, the coolant isn't topped off, thing with the brake fluid isn't topped off, so I'm wondering if this points to a need for new plugs? The engine (F22B2 [non-VTEC] 4 cyl, auto) performs fine at the normal 1,300-redline operating range, it only seems to do this if I raise it slightly off of its coasting RPM as I detailed above. I'm not really sure what this could be, plugs are my only idea so far :P

[VTEC_Inside]

Throttle position sensor is a potential.

[Secret Chimp]

I should also add that it doesn't do this if the car is stationary. I've nudged the gas as gently as possible and it'll slide up from idle past 1100 like a good boy.

EDIT: OK, this morning it seemed to a little (every several seconds, irregularly) and not as harshly as when in drive, but this was when the engine was cold and around 1500 rpm. I could barely tell.
Also, I haven't been getting excellent gas mileage. I got 24 on my last tank with mostly in-city driving averaging around 40-55 and a 100-something mile highway trip. I'm barely over 250 on the trip meter and I'm down to a quarter of a tank now.

[Secret Chimp]

OK, I don't know how I remembered all of this incorrectly, so redo:

It will misfire if I raise the engine off idle up to just under 1000 RPM if it's just sitting in park. It did it warmed up when I was waiting for my girlfriend to get some things out of my apartment. I went around back and put my sleeve close to the exhaust when it was idling to see if I could hear any irregularities I couldn't feel, but it sounded normal.

Another possible symptom is that it doesn't work quite right on quick starts from a dead stop. I haven't gotten the tires to spin on the thing if I need to stomp it off the line to make a left turn. It'll kind of act "surprised" and fidget around 1500 RPM (accelerating, but not terribly well) and then rev like normal after it gets closer to 2000 rpm and 15-ish MPH. I'm guessing it'd get going fine if I brake-torqued it. I don't feel the need to beat up on the thing like that, but just saying the problem seems to exist in the lower RPM range.

---Would it even be proper to call this behavior a misfire? I thought true misfires set off the check engine light, which hasn't happened. I do know that that light actually works, it came on when I test drove it due to a loose gas cap.

[3.0L V6]

If there's no CEL (make sure the light works though - look for it when starting your car, I've seen them burn out) the vehicle usually isn't misfiring.

Do a tune-up and see if these symptoms remain.