as with any repair of this nature, first the engine "normal operation" is verified - meaning fuel pressure, mechanical health and all electricals in place.
once the fuel pressure is verified then proceed to test the ignition coils - the way I test them is to connect a scope to "see" when the ECU is firing each coil - I also use an amp clamp and relay that into the scope too - this way I overlap the output and can see how many amps the coil is pulling when the ECU ignition timing signal is commanded..
The confirmation of a bad coil is that the timing signal is correct interval, but the amp pull was not there, confirmation of bad spark plug or missing fuel input is that the coil behaved normally but that cylinder failed an ignition event. If you saw black exhaust then the engine did get fuel - a small test on the injector with an LED or noid light can verify this.
leave that aside.
lets get to basics first - if your engine is misfiring on random cylinders then before any sort of repair - adjust the valve tappets correctly to factory specification, DO NOT let any jackass mechanic adjust them by "andaaza, tukka or hawaai fire" - you never know if the mechanic is diabetic and has numb fingers or is in need of nicotine to get his senses in order.
Install regular cheap as chips BKR6ES-11 spark plugs in there and install the coils with a little coating of silicone grease on the boots of the coils. Proceed to test the rest.
btw - what was the need to clean the throttle body?