My 97 kia sportage has no power going up hills

Could be alot of thing kia's a/c draind alot of horse power ,plus going up hill.try turn of a/c on hills.thats the owner of 3 kia's opinion . engine lacks power obstructed exhaust ,catylitic converter. defective plugs and or wires. fuel injection needs cleaned , air filter ,automatic transaxle fluid to much or to little and last my favorite the emmision control system . these are just the main culprits . only you can be the judge of how steep the hills are and how bad the power loss is