If most of your acceleration problems occur at highway speed, it could be a partially clogged fuel filter. Fuel demand is highest when at speed and when you accelerate, the additional fuel demand may not be met with a dirty filter. In my experience, symptoms of a partially clogged filter first show up at highway speeds and spreads to all driving conditions as the filter gets worse (which may take a while). I can't explain the jumping temp needle with this theory, but depending on mileage and maintenance history you should consider replacing the fuel filter.