missing

possibly a new fuel filter if only taking off slowly but if actually missing then tune up . first i would have it scanned for codes if no codes then tune up and fuel filter

Already changed fuel filter

is the engine misfireing running rough?

New fuel pump too it was driving fine until one day I cut it off then went back out to go and it started missing .

Yes sir

do you have any codes check eng light? normally this is either a fuel prob or a cat convertor there will be codes stored for the cat prob.

Yes sir check engine light is on and off at times. It has a small oil leak coming from up top running down on the oil filter.

you can have it scanned for free at your local advance auto orielys or auto zone near you. this will more then likely tell you where the prob is but sounds like a restricted convertor to me good luck

Could it be just one cat since it have three of them or anyway to bypass?

yes it could be only one the scan will tell you which one is causing the prob.

Could it be just one cat conv??

Estimated cost on that

My car is a 93 so I need a diagnostic from under the hood

they have adaptors for pre obd vehicles like yours.but if you want to confirm quicker just loosen exhaust at manafold and test drive. if this is not an option go to exhaust shop they can do backpressure test on your convertors and idenify the failing one .
cost prob under 25.00