Loss of power

Truck has no power to move with traffic cant go over 50miles an hour hard to get up hills backfire when pushing on gas trying to get up to speed I have replace plugs cam senor it start off good but quickly stsrt acting up

Getting new catalytic converter tomorrow n hope that do the trick should I get a direct fit or converter or after market

I have a 2001 Yukon XL I'm experiencing loss of power my vehicle, it will not go over 10 miles per hour gave me a bunch of codes I replaced the throttle body sensor or gas pedal sensor and the mass air flow sensor was driving perfectly fine after that the check engine light did not go out then it started acting funny again, please help.

General Motors thought it would be funny to put a sensor on your gas pedal hahaha joke was on me

My 2000 yukon xl will start in the cold/hot morning and idles okay, now after running on the road for about 30 min. I stop at a store for 10-15 min. Go back to turn yukon on, it starts but then it shking as if its losing power or gasoline. Yukon stops I turn key to start but it only tuns on halfway still sounds like low power or very little gas going thru gas lines, I dont know.I do this turning of the key a couple of times and all of sudden engine feels like its gets a full charge of power, either by gasoline or computer resets.I was told by a mechanic that GMC's and chevrolets fuel pumps get weak because of the cold.