No signal at injector, what next??

[invain]

One cylinder on my 240 hasn't been firing for quite a while now. After checking everything possible I had it narrowed down to the ground signal for the injector. I took the car to a shop and had them test real quick with a noid light for free and sure enough, no pulse at plug #2.

Before I go and spend $500+ on a new tuned ECU, is there ANYTHING else that could be causing no signal for only one injector. At first I'd though the signal wire had a short in it but I've replaced that with no change in the problem. I've been told if the CAS in the distributor was acting up it wouldn't affect just one cylinder.

At this point I have no clue what else to do besides try a new ECU.