Ok, with your help and a little from the data sheet , I ordered some 3 pin resonators at 8mhz and they work fine. Everything works at 9600 baud and all. I hook this project up to my car (ignition on, engine not running) and it works as it should. When I start the car, the display goes crazy with all kinds of numbers. This is what happened when I tried reading an analog voltage using a picaxe. It worked fine on the bench, but didnt work with a running car. I even tried a battery for power and only hooked up the serial line and a ground. Can a schmit trigger be used on a serial line? I can only think that there is too much noise on the line. I can hook that line up to hyperterminal though and it works fine. Any thoughts?

Jason