After some maintenance (including swapping injectors) my car is running horribly, like a cylinder is missing.

On cylinder 4, if I unplug the injector there is little to no difference to how the engine runs.
I have swapped over that injector to my original one and the symptom persists.

How can I test that the injector is receiving a pulse?
And what could be damaged that would prevent it from receiving a pulse?

noid light
http://easyautodiagnostics.com/misc-index/noid-light-tool-review-1

http://www.oem-tools.com/products/show/25142

Thanks Max
Can a multimeter diagnose anything?

nope, they dont read it fast enough, unless you have one of those $800 Fluke ones.
If you did, you'd know how to measure it ;)

You can make a 'diy' noid light with a LED in the plug terminals, it'll either be the right way around and flash or not.
At a pinch, you could also use a low wattage light bulb. at idle it should work just fine.

After some maintenance (including swapping injectors) my car is running horribly, like a cylinder is missing.?

Niod light for injector - but don't assume anything - check your plugs and did you remove the spark plug leads? and put them back in the right order?

Yes, new distributor cap, rotor and leads.
I've checked and the leads seem to be in the right spot unless I have no clue