i recently changed the head gaskets on my 91 305 tbi powered formula. ever since the head job i have had a skip. it is most noticable at lower rpms just off idle while cruising but is still there throughout the entire rpm band. it causes the car to lurch and shake. also my idle is eractic when, jumping from 500 to 900 rpms. she also goes through more than double the fuel she did before i changed the gaskets. i have checked and rechecked the valve lash, cannot find a vacuum leak and can't find anybody with any idea what is wrong. i also removed the smog pipes during the head job but don't see how that would cause a skip. anybody with any ideas please help me out here. by the way it is the stock hydraulic roller cam and i set the valve lash at 1/4 turn past zero lash. it seems to work better than any other spec i read. let me know if you have questions or answers.