My 96 z is not running too good. It really has problems top end .Seems like misfiring ,its very slow to rev out in third.
I see 12.3 or around 12 on the scanmaster for battery voltage. In contrast my 99 trans am shows more like mid 13s for battery voltage.
I put in a new alternator from gm a year or so ago.
I assume low voltage would likely make the car run badly from not enough voltage to the injectors and fuel pump?

 

I believe the scanmaster is reading voltage after the regulator, which is set to 12 volts to keep a constant supply to the PCM. If you put a meter directly on the battery terminals while the car is running, it should read the mid 13's.

 

Well in my 99 trans am my ls1 scanmaster is reading mid 13s when driving around. In my 96z my scanmaster is reading low 12s.
I think will swap my batteries today and see if the 96z top end problem goes away. It would be nice if a new battery fixes it. It better not be the alt since it was new gm and not cheap! Car has seemed to get slower over last few years even though have added more mods. Crossing my fingers ,if its not battery pretty sure it must be optipuke.Don't see any codes at all though.

 

Well, how did things work out for you?

 

Swapped batteries and didnt' seem to help much. Got bat and alt tested and alt might be a touch low. I will maybe swap it out have lifetime warranty on its its ac delco replacement alt a year or so old. But checked a few plugs and they seemed to be the problem. They are original it looks like with huge gap and looked really carboned up.
I could only get to 3/8 but even that helps the car is running better. I am going to not bother changing rest till next spring car is away in a couple of days anyway. I am doing my mac header install next season and hear plugs are simple to get to once you do that.
I did fuel system completely also. I put in new racetronix fuel pump in preparation for zex nitrous install. New fuel filter ,pro purged out injectors and installed fast adjustable fuel reg. I plan on msd opti,new wires and be running ngk 6 ix iridium plugs at .035. Car should run good then.
Also adding afr 180 elimintators and have alreacy comp 305 cam and 1.6 pro mag rockers.
Anyway worn out plugs seemed to be my major problem in the 96z.

 

I have ngk plugs also.. Very good idea waiting to do those with the headers out.. The plugs on these are terrible if you have headers.

 

Mac headers have great plug access..stock manifold plug access sucks huge!

 

The factory plugs are prone to losing the little platinum pucks off the electrodes. Lose one puck and the gap opens up to 0.075", lose both and you are at 0.100", and its going to start cross-firing on the wires, since the spark can't jump the huge gap.