i spent most of the day porting and installing a 58 mm throttle body in my 96 z28it started right up but the idle is higher then normal also bypassed the coolent lines. could it be cause of the more airflow thats my guess but not sure havnt done any mods like this before. need info thanks.

 

Yes, the idle will be higher and should only last a few hoursof city stop-and-go driving. Which throttle body did you get because some state that the idle will be higher at first once installed. Yes there is more air flow so adjusting the idle screw is sometimes necessary, just wait to see if the car's brain will bring the idle down.

I hope you don't turn out like me, I still have a high idle(1,500 rpm)after amonth!I'm gonna do a vacuum pressure check to rule out possible vacuum leaks.