problems with rb25 into r32

[Tizzle]

Just did the rb25 conversion into non-turbo r32 as seems to be the rage lately. Everything is done now and car is running even better than expected however after about a month of driving im noticing that the car doesnt seem to want cruise at say 60 k's and will very slowly loose speed, then when i put my foot down it is slightly unresponsive untill all of a sudden there is a small clunk noise and off it goes accelerating again. I think this may be a diff problem but there is no whines, launches are still fine and normally after about 15/20 minutes of driving when the car completely warms up this problem seems to either minimise or go away all together. Any idea's as to what this could be?? A new diff is on the to do list but i dont particularly want to be looking at this till late this year. I'm not sure if this is important either but I am running the rb25 gearbox and using a exedy heavy duty

cheers

[LBR33]

Check the throttle cable it might be loose

[race_snooze]

TPS throttle position sensor... Fuel pump...