Tach and speed attachinterrupt

I am using the Arduino Fio on an off road vehicle and was wondering if it is possible to capture both engine speed (tach) from a coil around the sparkplug in addition to wheel speed based off a reed switch and magnet?

In addition to these readings I am utilizing the CapSense library to have a capacitive liquid sensor based on this instructable: http://www.instructables.com/id/Building-a-Capacitive-Liquid-Sensor/

Also controlling an RGB LED and polling a pushbutton. All this data is being sent over an XBee back to a remote computer. Is it possible to do all of this on 1 Arduino? If not my plan was to have 2 attiny85's to sample the tach and speed separately and then send that to the main Fio.

Any thoughts?

Thanks in advance! Ed

I can’t comment on your choice of sensors, but what your are trying to do in principle is well within the capabilities of an UNO. If you wanted more interrupts to monitor all four wheels, you could use the pcintchange library -

Duane B