power loss?

ive searched but cant really find anything specific on my problem. i have a 91 4.0 4x4 h.o. and it doesnt have much power. ive heard if the cat is clogged it can make it do this, but i also dont have good vacum. i read somewhere that a clogged cat will make u have low vacum and u will hear a whistling. my dad has a 92 identical and it has about the same mileage and he has plenty of power. anyone heard of these symptoms on a clogged cat?

how many miles? what is your vacuum? i think 17 is the magic #. low vacuum could indicate a clogged cat, or a vacuum leak. my cat was in terrible shape but never affected vacuum or made a sound. do you have problems acclerating over 3k rpm?

its got 183,000 on it, not sure about the vacuum, when i accelerate more the dash vents kinda fade out and go to defrost, and when i let off it goes back to the dash. but i hear a whistling in acceleration and i dont have vacuum leak, went over everything. it only has problems accelerating at lower rpm's.

Yes, a clogged cat will do both. An infernal combustion engine is nothing but an air pump. Vacuum is generated when it pumps air out, and then needs to refill the cylinders. If the cat is clogged and it can't pump the old stuff out -- there's no place for new air to go, so no flow, so no vacuum.

anyone have suggestions on a new cat or maybe take it off?

you could use a cat i think, just by the miles. i would recommend a cheap one with a heat shield.