Pico 3000 vs 4000 - frequency graphing question

Two questions:
I'm researching which pico to get and then I read that the 4000 can graph frequency but the 3000 cant?
1) Does this mean that i cant test digital mass air flow sensors with the 3000?

Another key feature to the 4000 series scope is that it has the ability to look at 'Frequency' through the hardware of the scope i.e. as a coupling > DC > AC > Frequency. This again is a need for modern technology where we are starting to see a significant increase in digital electronics i.e. Digital Air Flow Meters.

Ref:
www.picoauto.com/support/topic9095.html

2) As a heavy duty mechanic who works on on/off highway equipment is there a benefit to getting the specialized 'automotive picoscope package'? is there anything different about the scope itself or is it just accessories included that make it auto specific

The 4000 is a really sexy bit of equipment. This is a really great question the frequency graphing is a 4000 only feature because it requires a large amount of processing power to do it in real time. This really makes testing a digital MAF particularly on a gasoline engine much easier because you can capture the spike on a throttle snap. However I find the MAF on diesel engines are easier to test because diesel engines don't throttle the intake air and the MAF signal tends to correspond with RPM, so a steady RPM test works and this applies to both analogue and digital MAF on diesels. But you really need to have known good values to compare with.

So the engine can be held at constant RPM values and the frequency measured either using on screen rulers or a provided on screen measurement which many scopes have.

As to if you need the most expensive all in one kits, all scope accessories can be found either from various sources www.scannerdanner.com/dmm-and-lab-scope-accessories.html Just about all proper oscilloscopes standardise on 1 Mega Ohm input impedance so you can mix and match generic oscilloscope probes, current clamps and accessories. Pico use a a standard BNC style connector but on eBay or Amazon you will find adaptors that will allow the connect of multimeter style 4mm banana plugs.