I have a Techtronix scope from the 80s works great and you can find these cheap on ebay from time to time. These where top notch scopes back then and are way more than you will need. see listing #260208297748 on eBay for a good example of one. This one is very much like what I have. Here's another on ebay 220152729815
Then if you have a loptop you have new bread of scopes like this on ebay 300196854456, never tried one but sure seems cheap and you view the image on the laptop. Plus easy to record stuff. I'm tempted to get one of these myself.
As for Gas anylizer that in my oppionion is old school. I bought a Wide Band O2 system for about $200.00 and it's amazing what you can do with this thing! Beats the Gas Anylizer any day for what we need. I much rather know Air Fuel Ratio. Here is what I bought:
http://wbo2.com/2j/default.htm about $175 shipped
Then I just bought the WBo2 sensor from Autozone Bosch #17104 for $50.00
The software is free.
See this thread for the project details:
http://forums.pelicanparts.com/showthread.php?t=364450