I just want to chime in here, my car used to do this up the big ass hill on my way to Work. Went away when I shifted down to 3rd. I was clueless as to what it could be after tons of research and checking everything I could think of. A few weeks later I get an intermittent cylinder 3 misfire which progresses to a constant misfire. After plugs, wires, coil packs, etc. it wouldn't go away. Misfire ended up being a bad injector and since.replaced, the misfire and thee surging uphill has disappeared