actually im not sure if it is the opti but it seems the easiest to blame right now. car is a 94 so non vented opti...has very bad stumble/misfire when wet...no ses light for misfire...i thought i read somewhere it blinked for a misfire...but it did come on once last week when it got really bad...the thing that would lead me away from the opti is that as soon as i put in the clutch and rev it it revs fine...get it back in gear it stumbles and seems to misfire...give it some gas and they pick up again and rear slides out...anyone????

 

I would look at the ignition coil and spark plug wires as most likly causes. the opti, while being a problem dose not get wet and dry out, if water gets inside a non vented opti its there for a long time

 

so why would it only miss when im in gear?

 

and only in a certain rpm range...as soon as it passes out of that range it jumps like i mashed the throttle....but i could have been holding the gas in the same place for about 1k in rpm change

 

for ignition missfires on N/A cars (no turbo, Nos, ect) missfires tend to happen a lower RPM there is less ignition timming at lower RPMs the spark has to accur in a higher pressure inviroment at 10 before TDC than 36 BTDC.
we here on this board can point in a posible direction but with out beeing there and testing can not be absolutely sure. from what you are discribing it sounds like a week secondary ignition spark plug wires, ignition coil, and yes the opti. but if it only accurss when wet the opti would be less of a posible problem because of what I stated ealyer.
In my opinion opti's or atleast the cap and rotor should be considered a maintanace item and replaced like a timming belt every so offten posibly even with every tune up -60 to 100,000 miles

 

how would i go about testing where it is?...should i just start by replacing plugs, wires, and the coil? the car has 118k mi...

 

if it dose seem like a ignition miss fire and the check engine light is not on. the plugs, wires, and coil would be the first place to start and while your at it replace the fuel filter to.
I personaly prefer using stock replacement parts such as spark plug wires those fat MSD ect wires do not fit as well in the tight spaces of the LT1 engine. go with A/C delco, dealer parts, or if you go to a parts store car quest has some of the best quality parts. stay away from checker and auto zone

 

i bet its the coil wire. the opti end is located behind the water pump and the coil end... well the coil end is attached to the coil a friend had the same problem and was gettin ready to tear down to junk the opti, turned out his coil wire was all burnt up. just somethin to check before you bust your knuckles replacin plug wires or spend a day replacin the opti

 

Mine did the same thing this weekend it had been running fine all night except for a random miss at high RPMS which i know is the opti going out but i was talkin to my friends went to put it in gear (a4) and it almost died it kept running at like 400 rpm and would stumble bad to 1500 rpm then rev fine. Then my friends told me to shut it off cause it was smoking badly, i thought it was an electrical fire, i popped the hood luckily no fire the damn mass air flow sensor touches my coil wire boot on the coil and it rubbed a hole in it and started jumping the spark to the MAFS instead of through the wire.

In your case that bad of a miss that comes up that randomly is probably somthin like i had or bad wires most likely not the opti, the opti will usuallly give you a fare amount of warning