bad hesitation on my new mkII

[SolidStateS15]

i just picked up an 85 mkII and am trying to get the lil old 5m going again till i get the 7mgt swap done. it's acting very weird, and when i got it the person said it was a clogged cat. it is acting something like that, where it just has no power and when you even sit at idle and floor the pedal it does nothing for like 10 sec then finally the rpm's will start to climb slowly but still not gain much. i pulled the cat and that didn't help, and it didn't look that bad. i also changed the spark plugs which were in horrible shape, but still didn't help. my next things are fuel filter, check for vac leaks, and check some other ignition stuff. i'll do a compression test, but i don't think it's the HG since there aren't other signs of it. i did pull the intake apart and made sure it was all tight and put on a new cone filter. the last owner has already installed a new coil and plug wires, tps, cap&rotor, and a few other things. i was thinking the tps could possibly be off and may need alignment. not sure what else to look for since i am new to these engines. could a bad clutch cause this? cause the clutch does seem pretty weak, it's probably original and there's 165k on the it now. not sure what would affect the rpm's like this.