If it is a missfire you would usually still have one at 1500rpm and when you accelerate quickly under load it should miss fire still if it's a weak spark due to an introduction of more fuel which will help to extinguish the spark hence engines with weak spark will flood. If you are going to pull off the HT leads then use a lead light with the bulb removed at the end of the HT lead connected to the battery negative to divert the electric safely to the battery. Pulling leads off is an old technique to check for a miss fire but it will allow 10,000v to pass through the engine which has numerous 5v sensors and 12v actuators it's not really recommended any more but it will still work if you don't have tools like an occiliscope to test components but this will help to identify if you have a miss fire from 1 cylinder. You would get a crack from a weak spark and injectors will make noise but if you can get to the fuel injectors easily you can unplug 1 at a time it will give the same result in testing as pulling ht leads but you won't be throwing unburnt fuel down into the catalytic converter and damaging it if you can get to the injectors. I have had a timing chain tensioner fail before when an apprentice put the wrong oil grade in the car