SR bogging

[xekret]

Im having a little bit of issue with my S14 blacktop. Car runs fine for about 20 to 30 minutes then it starts hesitating just a bit. I was driving today and it just bogged it didnt die. I tried to rev it but it would not rev and then go up slow and not go pass 3500. Then after sitting on a parking lot for about 3 minutes it all went back to normal and drove off. I thought it was the fuel pump and replaced it with a walbro already. Car also has a z32 fuel filter so I dont think fuel delivery is the issue. Any suggestions will help. Thanx