When you start it up it sounds like a monster but when I drive it doesnt seem to be putting out as much power as an IROC-Z should.. it seems kinda sluggish.

Well, I know it needs a new battery, I have to jump to start, would a bad battery take away all that extra pep?

If its not that let me know where I should start checking and what I need to do to get this IROC up to par. I recently bought this knowing it needed a lil work and am ready to get her movin like she should.

All your help is appriciated

 

Batt would not do that>> besure the pre owner did not
pull out the bulb from the check eng light>>> try to pull a code
from car>> lots of things to check injectors, spark volt, mass air flo
ect