When im driving after it warms up sometimes if i give it too much gas itll just bog down. It also just feels like its in the wrong gear. itll accelerate really slow. my friend suggested it could be the air filter. im new to all this so i need a little help

 

only does this when it gets warmed up?

while there is no more info regarding your truck, i'd check out your cat first.

try drilling a small hole (3/8") an inch or two in front of the cat. this will relieve some of the back pressure if the cat is plugged, broken or obstructed somehow. now go for a test drive, it should run a little better.

the hole is small enough that it can easily be welded up with the mig welder after.