Mazda Tribute 2005 doesn't have enough power
 

My Mazda Tribute 2005 2.3L isn't getting enough power I can maybe drive in like third gear and maybe at 40 miles, there are no engine light or anything I tried switching the spark plugs with older ones from an older engine (i had to buy another engine because the older one was just garbage). please help i have no clue and just ask for anything you need like pictures or any more info.

how is your oil consumption?
Possibly do a compression test.
Ever change the PCV valve? ----- Mazda never did.
I don't even know why i'm bothering with this as you say you bought another engine.
How are catalytic converters----semi plugged----are there any cats on your vehicle not minitored with O2 sensor?
Air filter clogged?
Ever put fuel system cleaner in?
Ever clean your throttle body or MAF?
Ever change your fluids?
Without me looking at the engine and you having some knowledge, my advice is just ridiculous!!!!!
It's like trying to explain to a little kid when he says "WHY".
Just take it to a real mechanic, please.