when accelerating my car will sputer and it usally happens when in high rpm or after 2000 the tack will jump down then back up its a rebuilt engine with under 40000 on it i think it mighht be my coil packs any suggestions

 

Sounds like it could very well be the dreaded 3800rpm stumble. Do a search, there's been a lot written about what causes it and how to fix it.