93 gmc 350 4x4 power problem

i have noticed alittle power lose in my truck. seems to not pull the power it has been in the past. checked the engine over everything seems fine????
done a tune up plugs rotor cap the works. almost seems like something is holding it back.
could it be the converter??? i had a converter go bad on a 91 caviler but when it stopped up it lost alot of power quick.
let me know what you think.
thanks

Did you replace the fuel filter? Have you checked fuel pressure?

Not sure if this is the same issue but maybe it will help you. My 90 GMC started to take longer to shift into 3 or 4th gear. It was not slipping, it just took longer to shift into gear. I changed the fluid and filter but no change. So I started to research what it could be.

For me it turned out to be the seals in the servo (especially the 4th apply servo). I spent too much money on billet servo but I think the vette servo (around $20) and some new seals on the 4th apply servo would have been fine for my truck. All of this can be done without removing the pan!

It now shifts much better.

thanks for the reply i will try the fuel filter first just in case.... dont think it could be the cat converter???? if the filter dont work then i am thinking about taking a closer look at the cat converter