if its not the air filter, check for a bad wire connecting to a cam sensor on the bottom somewhere. could be messing with your timing.
but while checking your filter, check your MAF sensor, and make sure water or vapor isnt hitting it.
2002 GT 5sp. 16x,xxx miles
Steeda Exhaust, C&L plenum, BBK Throttle Body, Steeda Underdrive, Steeda short throw, unknown stage clutch. Rear main leak. Compressor seal leak. Steeda lower control arms. good tires.