hey everyone. my 89 2.6 isuzu trooper is having a little trouble. it starts up just fine runs and idles just fine. but after Ive been driving for about 30 minutes it starts to get really sluggish and if I press the accelerator I have no power at all and then it will just end up dying. once it dies I can start it right back up with no problems and it runs fine again for another 15-20 minutes before I have the same problem. its not overheating when it does this and I have plenty of gas. any thoughts?

Thanks
Chris