i work with RPM controllers and speed limiters in the automotive sector and short of 2 models of the latest fuso trucks, all trucks and cars (and forklifts) with an electronic throttle dont care if its a linear voltage or PWM, (the fuso's have an ac coupled data comms)
as far as pedal signals go, short of a few odd chinese and one american car these signals have been run straight to the ECU and digitised there, for all of these a $10 multimeter will get you within spec, record the high point record the low point, and for older models record the IVS threshold, (range is linear)
as for decoding CAN a scope may be the wrong approach, if you only care what is being transmitted rather than if it complies to the voltage and timing standards a logic analyser is a far better choice for when you are on a budget,
hope this helps,