2000 Kia sluggish acceleration

“My 2000 Kia won’t go over forty miles an hour. It has very poor acceleration, but it idles totally normal, smooth as can be. I’ve changed out the fuel pump and filter, but it made no difference at all. HELP! “

Well, you took a good guess, but it’s probably another common problem. Now assuming the fuel pump you bought is good (just hook up a fuel pressure gauge and test it–pumps can be bad right out of the box, especially aftermarket pumps), then odds are you’ve got a bad catalytic converter (or bad converters as that Kia has two cats on it.) As I’ve shown in one of my videos, engines have to breathe in and breathe OUT to function correctly. If the cat gets clogged up, then your engine can’t exhale and will only be able to drive up to a certain speed, and no further. Have the cats checked and replaced if they’re building up too much backpressure.