A couple weeks ago my firebird started bucking every now and then while I was driving. Then one day it just died coming onto the interstate. I pulled over car would not start I found it was not firing at all. It would turn over but no spark. Later that evening I went to get the car and it started right up. Next morning same thing it died and would not start. I replaced the fuel filter and and the ICM. It run fine for a week now and now it is doing it again. And it shows no trouble codes. Any ideas?