2002 3.0 Electical issues

[st-ranger]

I have been having electrical issues, first one was battery wouldn't charge. Autozone tested it and said bad alternator. I replaced the alternator and, of course that wasn't it. Put a know good battery from another car of mine in and same problem. Engine wont start after sitting for a night. I hook up the jump box and it fires right up. I also noticed that when it is running it wont rev over 3000 rpm, like hitting a rev limiter.
I have checked all the grounds around the battery. it gets power when the alternator is charging.
I'm at a loss where to go next.

2002 single cab Edge 4x4 3.0 Automatic

 

[pjtoledo]

to test for a small battery drain get an amp meter, one that can handle 10+ amps. hook it up in series with the pos cable, I would include a fuse for safety. then start pulling fuses and relays to see which one kills the current draw.