my 94 z is acting up lately and at idle it is shaking and when i drive its rough and has lost power, but when i rev it with out driving it revs normal, im thinking its something in the exhaust... maybe clogged cat.... any ideas

 

i think it is cause im havin the same problem. one day i picked up someone in my shop, and he said it might be the exhaust. then last night i was coming on base and i asked the guy that was checkin id's and he said there was some smoke comin out. He said the cat might be goin out or clogged. goin to a muffler shop to see how much they would put my headers on and see if that know what the problem is.

 

yea its sorta hard to explain i just started it up the other day and it was shaking at idle more than usual and didnt have barely any power but i know its not missin because it doesnt stumble its just rough throughout the whole rpms

 

My guess would either be a clogged up cat, to which you should unbolt your exhaust to see the effect that has on the revs. (get the cat off)
or
a burnt plug wire/wires.

 

yea a clogged cat was the only thing that came to mind to me actually... does it sound like maybe a vaccuum leak like the others said, if so how do i check those?

 

bump, its misfiring and there is a weird sound coming from the coil in the ignition system do you think replacing this would make my car run right again?! or plugs? help!

 

Checking all plugs and plug wires is what I would do first. It could be just one wire (or plug) causing your miss.