Google MAX9924. It is a VR conditioning chip that will do just what you need. It is used in many aftermarket ECU's for the VR input.
Hi,I have used the following circuit to read the RPM of a VR crankshaft sensor of a motorcycle engine.A slight error in the circuit, it says "From ECM". This is actually from the crankshaft VR sensor.The capacitor removes the DC component, if any. The first diode is a fast switching diode, 1N4148, this removes any negative voltages. The second diode is a 5.1V zener diode, BZX85C5V1. This makes sure that the voltage does not go above 5.1V.Then the schitt trigger cleans up the signal to a nice square wave that can be read by an Arduino interrupt.The wheel on my crankshaft has 12 teeth, but it does spin at up to 16,000 rpm. This means a 3.2 kHz signal at full speed.Your engine at 6,000 rpm and 60 teeth will be producing at signal at 6 kHz. I'm not sure if this is possible for the Uno but I would imagine it is.
I don't actually have a scope, so I'm unable to confirm if the small negative voltages still exist. I am using a schmitt trigger to condition the signal further though, so that could remove the negative completely.It is working fine for me.Here is a short video showing my project in action: https://www.youtube.com/watch?v=mq24VVuxbAsIt is reading the RPM using that circuit and displaying it on an LED strip.
You might also look at a LM1815. It is not as hard to implement as the MAX9924.If you have any problems understanding the MAX9924, go to http://www.msextra.com/forums/index.php and search for MAX9924 or LM1825. There are a lot of threads dealing with these chips.