injector open alarm

[ipasgas1]

I have an open injector alarm on my smart engine monitor (2005 Searay 390 MY with twin 8.1 Mercs). I had it checked 6 months ago and the mechanic found nothing wrong and alarm went away. Today, it is back. It does the 2 beeps/min unless I run up over 3000rpm then it seems to beep rapidly. One shop I spoke with says I will need all new injectors and it is a large, expensive job. Not what I prefer to hear. Any ideas? Could it just be sticking and I can kick it :O) Can it be a loose wire or is it always bad?
Thanks,
Dan

[ipasgas1]

Now, both engines will only rev up to 3600 rpm and the solid tone is alarming?

[NoTies]

Check continuity across the terminals for the injector. If all OK, try an ultrasonic clean. I have done this with varied success in the past.