Ok, here is my problem. When i'm at a complete stop, it'll take a lot of gas to make it go, and as soon as I disengage the clutch, it'll sputter a little then go. Also, if i'm in a lower gear at a low speed, it'll sputter like this also as if i just started driving stick. I doubt its my spark plugs or anything like that because i just performed a major tune up on it a few months ago. However, I do know that my cat convertor does need to be replaced, cause I know it has some holes in it and you can even hear gas coming through the holes. Could this be my problem? Maybe the cat is clogged or something. I hope someone knows what this could be cause my car is running pretty sluggish

vacuum hoses then O2 sensor one by one to isolate the problem. HTH good luck!