do a compression test

 

what are you thinking with the compression test? i would think that a problem with a valve or something would have one of the plugs very rich or very lean...and a piston issue would have some noise, and oil on the plugs..no?
the car still runs pretty well..no smoke, nothing...it just sounds like an STi now...

 

well i was thinking toasted valve, but now that you mentioned the plugs not being fouled, im rethinking that. id do one anyway just to double check

 

cylinder leakage test can be another way to locate the problem.

 

ill see if i can borrow a compression gauge around here...but i think that any problem with the valves or pistons would result in some effect to the plug...if an exhaust valve was hanging, it would be burning super hot in there...and if an intake valve was hanging,, i think that it would be very lean on that plug, but theyre all the same, and none look very lean. if anything, it seems like its rich...

 

well if the valve is hanging open, then there may not be enough compression to ignite the fuel, which means that it is going to appear rich.

 

if its just one the computer will compensate....either tell more air or more fuel....

 

i agree, but wouldnt you guys agree that if it was a valve issue, more likely than not there would be some signs on the plugs? its cold and supposed to rain here today (and its supposed to be like this all week), so im not going to have a chance to get to it for a while..but i appreciate that thoughts on the subject.

i did start the car last night to move it out of the way in my driveway, and it was missing...this morning for ****s and giggles, I started it up, and it was fine...drove it around the neighborhood, still fine...

 

when it starts misfiring again, unplug the injectors to each of the individual cylinders one at a time and see if it changes how the car runs, the one that doesn't change anything is going to be your misfiring cylinder, then you can check to see if you have spark and fuel on that cylinder

 

well, per the advice of a mechanic, i pulled off the coil pack. i understand how to check the secondary resistance, and i got a measurement perfectly in the middle of the desired range, but i dont understand how to check the primary resistance. the reason that i went this way for now, is that the computer is also new (within the last few years), so if its a spark issue, it almost has to be the coil...a visual inspection of the coil did no good, as im pretty sure that its original, and its SO filthy and caked with grease (the valve cover gasket was bad when i got the car, so its a mess back there), that i cant see any visual damage of any kind, and if i can check the coil for proper function, that eliminates one of the possibilities.

thanks again for the insight everyone.