Problem in high gear going up hills

I have a 2000 limited 4runner with a 3.4L and auto trans. The problem I have happens in high gear going up hills the engine begins to miss terribly until I reduce throttle input or downshift. It has a cyl.#3 misfire code as well. I feel like it is likely the fuel pump since it has 180k miles. It runs just fine on level or when in a lower gear. Any advice would be greatly appreciated!

 

Not a fuel pump.

I'm going to say you have a coil going out on you. Generally a fuel pump works or it doesn't. Remember it is an electric motor.
Pull the plug in cyl 3 and look at it. Try this the coil that fires that cyl switch it around. If the miss fire moves to that cyl then there you go.

When was the last time you did the t belt?

I'm not saying they are related but it is time again or at least getting close.

Blue

 

Replaced the belt for the second time around 6,000 miles ago. Why does it only seem to miss going up hills?