Ok this KIA runs good, starts good, rides good, has no miss in the engine. But when it hits a hill it loses power which it didn’t do before. The plugs and plug wires has been change and alot more has been done but it loses alot of power when climbing a hill like from 60 mph down to 30 mph.
My guess is a clogged Cat Converter.
If the fuel filter wasn’t included in the many things that have been done then you might consider trying that.
Is the check engine light illuminated? Also what is the year/model?
As Joseph mentioned the symptoms fit with a posible clogged cat & testing for that possibility is simple enough:
From the instructions that came with my 20 buck vacuum gauge:
Note gauge reading at idle
If gauge reading increases over 10 hg as engine speed is increased to approx 2500 RPM’s the exhaust system is not restricted.
If the reading drops toward zero as RPM increases, either the exhaust system is restricted or an overactive EGR valve is causing the problem.
You can do this simple little test yourself, or have your mechanic do it.
the check doesn’t come on. it’s a 2001 sportage. also the inverter was remove 3 years ago