I just rebuilt my motor top to bottom. Bored it .30 over with flat top pistons and an RV cam. When im driving though it seems to cut out when maintaining speed on the highway. Its almost like a misfire. Could this be a computer issue because i have the same computer with this new motor?

 

I'd take it to a specialty shop that can flash the prom since you didn't go back to what was in there more than likley it needs reprogrammed with your changes.