"You dont have plug wires the SR20 uses coilpacks. I can gaurantee it's your plugs if its going on only under full throttle. Either that or you TPS isnt adjusted correctly or not working. Do the plugs and gap them to something like .35 if your running a basic setup"
Thats a response to the original post in this thread...
redtop sr20DET hesitation...WHY? - Beyond.ca - Car Forums
Then there's this post of interest...
"GONEINSANE my friend i laugh at your question! Why you ask , well i had the EXACT problem and i can give you a little bit of info and hopefully it will help. Does this problem happen when you floor it or change gears real quick like when you race off the lights? It hesitates for a bit usually revs dropped to between 2-3000 then it will take off. Doesnt have to be racing still happens every now and then hey! Well it took me months of trying to figure it out. Firstly check your KNOCK SENSOR, it could be retarding the timing, to check this all that needs to be done is have your mechanic hook it up to his computer and it will say if it is causing a problem. I changed my fuel filter, fuel pump, sparks, computer, air flow meter you name it i changed it. Didnt fix anything. If you have an aftermarket BOV it could be causing it too. Sometimes it plays with the computer adding a new BOV. Make sure your stock one is completely disconnected. The last thing to do is advance the timing a little. I guarantee its not the pump, what helps too is a custom dump pipe, i bet you have a cat back exhaust. Get the full exhaust system get your knock sensor looked at and BOV if not then ?????? "
Taken from this thread
SR20DET Hesitation - Hardtuned.net