I have decided rather than try to use my amp clamps, just buy a good Fluke clamp on amp meter that is accurate and that I can trust. What is a good model to get and why?. I want to do DC for automotive work, but am unsure of what range and model to get. AC amps would be good too.
I can't help you with clamp-on meters, but I <3 my Fluke hall effect sensor. Cost over $400 though, and you might not need its capabilities.
Do you need to measure smaller signals? The i30 can measure down to 30mA, while the much cheaper i200 has a 500mA floor.
Here's my back-and-forth between the two:
http://toolguyd.com/fluke-current-clamp-multimeter-test-leads/ . Ultimately I went with the i30, and use it with a couple of different general purpose meters.
The Amprobe LH41A is also a Hall Effect clamp, but is a full clamp-on meter, not just test leads. Priced at around $380.
Sorry, I don't know much about automotive current sensing needs; sorry if these leads are way off. But if you need low current capabilities, then Hall Effect is the way to go.