it acts as if its misfiring. it bogs unless i WOT the thing. only when its been running for a while tho (more than 15 minutes). sometimes it will just die at idle. ive replaced the coil packs, wires and spark plugs and nothing has fixed the problem... what could it be?

 

Time for a compression test?

 

could it be anything else? clogged injectors? bad timing? etc.

 

Water thermo sensor is a good candidate.

Other possibilities include vacuum leaks, BAC valve, air bypass solenoid, and air flow meter.

Check for trouble codes. If there are none, I would pull up the carpet on the right side, and backprobe the pins on the ECU connectors with a voltmeter. Compare the readings with those published in Ch 4 of the service manual, especially the one for the water thermo sensor. By checking the voltages there, you are checking not only the sensor but also the wiring.