Car won't boost
 

Pulled my car out for the spring, took quite a few jumps and she finally started. Anyway, I let it sit for a few weeks as I was waiting for parts, now she won't even start with booster cables hooked up. Reads 13V while hooked up (on dash and multimeter on battery) but when I crank it the voltage goes to zero. Then charges up again.

Big 3 is done, battery is fairly new, upgraded alternator...

I started testing my fuse box for shorts, and found a few ohms and megaohms resistance coming from the ignition fuses. I'm not sure if they're standard resistance numbers or not, waiting for a mitchell printout.

What is the next step for my diagnosis?

VATS maybe?

anyone??

most likely a vats problem.