z_speedfreak

iTrader: (3)

ok I relize this is a hard question to answer, especially throught the net, so im just looking for pointers basically on what to check out. my Z has ben sitting for the winter I start it up and let it warm up about every other week, not too long ago i started noticing a VERY slight miss while idleing that will occur about every 8 seconds and like I said its very slight, almost un-noticable. there also seems to be a little bit more vibration running through the car(while idleing in neutral), then last week I took it out for a quick spin, I didnt let it warm up completly and going out of my drive way it bogged down almost stalled pulling onto the road, but then after that my camaro was pulling hard like when I first got it and I know its not just because i havn't drivin it in awhile, I was breaking loose in 3rd gear! I have to shift 1-3 because I need a new tranny so usually its a little sluggish unless i really bring up the rpms in 1st but going from 1-3 seemed just like a 1-2 shift, I even had to check to make sure i put it into 3rd and not 2nd it was so surprising, I'd shift into 3rd and it would start pulling, then after a 2-3 seconds the power would just explode and my rear would break loose, my car hasn't seemed this strong since it was brand new to me, i could break loose in 3rd gear then too but i had bad and compleatly BALD tires on it, my new ones hold the road way better and it was doing it with out me even trying. I suspect my opti is on the way out since I just hit 90k miles, does it sound like it may be the culprit? im not complaining about how strong its running right now, but some thing isnt right with it cause off that off beat in its idle and while sitting in the drivers seat, revving the engine a little, you can definatly feel some extra vibrations, maybe my cat is getting a little clogged too?
what else should I check out while im under the hood searching for the problem?