I just bought an 85 z28 with a 305.

The car had a battery issue when I bought it. It woudl crank, slow down, speed up, slow down, speed up and fire. Sometime it fires 1 crank and goes. Ignition seems fine, fuel seems ok.

I cleaned up corrosion on the positive post, and it worked much much better. Last night I fired up one crank and go, perfect. Drove it all the way home stalled it on my driveway(shutup) and it would act like a dead battery, Cranking and slowing down.


I just left it in the driveway... Today go out and fires on one crank, like a new car.

I am starting to wonder if the starter is going bad, that maybe it gets heatsoaked and has some issues.

 

I am leaning torwards a weak battery, I gotta find my multimeter and check it under load. I had the AC/headlights on lastnight. Today I tried starting it with both on and it really struggled.

 

Under cranking loads it drops down to about 10v, which from what I believe is still good.