Runs fine going uphill but starts misfireing going

try checking your crankshaft or tps throttle position sensor it could cause you to lose power at times

When was the last time you changed your fuel filter? I had a truck, exact same problem then it started stalling out going up hills, was a plugged fuel filter

No sure the question-- only the uphill part

Egr Systems problems
Cylinder Misfires
Vacuum Leaks
Spark Plugs
& more

Discharges--the battery?
Do a parasitic current test

Seal trans fluid--you did or have to--- what's that about?

sounds like a coil misfire, check codes. My astro van did the same thing going uphills. New plug wires are cheap and easy to replace.

fuel filter clogged? fuel pump problem? Maybe Injector bad (TBI) or screen stopped up with rust around injector.

go to auto zone get codes what year? distributor, tune up, bad ignition wires, vacum leak need more info

could be your coils?

CYLINDER #1 & #7 MISFIRE DETECTED.

Take it into your mechanic ASAP before you throw a rod and destroy your engine, check oil level also...DO NOT DRIVE IT ANYMORE or you may be looking for another car soon.

A couple of things can cause this. First, make sure that your fuel filter is clean. next make sure that the fuel pump is putting out adequate pressure. I'd also check timing to make sure it has not been set too far retarded. A bad ignition wire or spark plug can also give you similar symptoms but generally you would feel a slight miss at all times but sometimes unless "loaded" it's not as obvious as you would think it should be.
Obviously I'm not there to drive it but the items I've listed are where and in what order I'd begin to check.good luck!!