Acceleration Problem

[Powerzen2002]

Ok, heres the deal.  Take off has been a little sluggish.  When going on the express over 50 and  I take my foot off the gas, the car feels "wobbly".  

Yes,  I said "wobbly".  Its like a studdery feeling, however if I play with the accelerator, it feels as if the car is wobbly.

Now, I just replaced the O2 sensor (by the manifold).  Now, heres another thing.  I put my hand under my car to notice there is a small air leak coming from my Cat.  Is there any relation possible?

Thank you.

[importrza]

sluggish acceleration can be caused by may things. If you cat it could it will turn cherry red (from build up of exhaust gases, but only if it's seriously clogged) I had a cadillac once that had a clogged cat and the symtoms weren't what you are describing it would not accelerate even with the gas pedal all the way down if fact under full acceleration it would start to slow down. It could have to do with you fuel system(clogged filter, injectors, fuel pump on the way out).

[Alias]

I had a leak right after my cat and it afected the cars "peppyness". I fixed and it went away, then it leaked again:( My Grandam had a plugged up cat. It got hot enought to make the shifter warm in the car LOL.