I have a 95 automatic transmission lumina with around 130K on it. The problem is that at around 45 mph, the car seems to hit a lull and will not accelerate. I have to floor it and after 2 or 3 seconds, it begins to accelerate normally. The problem is also sporadic and does not seem to happen every time I drive the car. I've asked the opinion of a few mechanics, each one giving me a different answer. One guy says it could be the shift cable, another says the transmission needs to be replaced, another says I just need to get my transmission fluid flushed.
Any ideas?