runs like crap for a few seconds everytime

i have a '98 durango 4x4 5.2 v8 and heres my problem

i have a p0135 code, i just installed a glasspack on my '98 durango 5.2, the code came on a few days after i did the install, Now the problem that i want to get rid of has been happening before i even installed the glass pack, heres what happens everytime i start it up and go down the road a few miles then for a brief moment i loose power then she goes back to normal. Even when i start it up and let it idle, i dont touch the gas at all or put it in any gears after s few minutes like 1-2 minutes the idle gets crappy just for s brief moment like 5-10 seconds then goes away and idles fine. soo no matter if i drive it or even let it idle it runs like crap after a few minutes every time i start it up for a few seconds.

Check the H02 sensor wires for heat damage, a short could of blown a fuse going to the Heated sensor.

Do you happen to know where that is located? on the cat ? Also should i check that fuse ?