Expensive Cadence Meters, aside, new pedals aside; (not that you bike fit might be off or whatever since I don't know you and have never seen you ride); You need to train your weakness!

we all have them. whether its hills, small blips. a heart rate monitor might help you understand what your body is doing. But from what I am hearing, if you are coming into the blip at 18 mph and you are running out of steam at the top or before the top and then have to slow way down to recover, you are going over your lactate threshhold and you are having to reduce your workload to recover. So, even if you think you are not working that hard, it really sounds like you are pushing your limits coming into the blip and pushing past that threshold while on the blip causing you to blow!