Like already mentioned, if you have a laptop have a look for the hantek1008 or the picoscop 2204 A .The hantek is a 8 channel one while the picoscope has only two channels. Both are about 150 bucks and work pretty well for us nechanics. If you download the picosoftware first, you may see a lot of examples what to measure on a car. Of course you may buy one at a much higher price and become an electronics. :-)