before you get to the top of amp plains, try and recruit an electrike, that should help you alot!(it has the lightningrod ability)

Hmm, when i did it a second time after restarting my game and getting mudkip as my starter and cyndaquil as my partner, I tried to get an electrike but i failed so I moved on and I went through the fight pretty quickly. Cynder had smokescreen and lava plume, and I havde like 4 reviver seeds and stun seeds to keep luxray from doing much.