okay so the other day i was in my car, (94 grndprix 3.4) i went to turn on the radio....well i kind of like started to start my car, but then turned it off. i didnt realy think anything of it. so i went to start it like 4 hours later when i did it revved to a little over 3000 rpms then dropped and died. it continued to keep doing this. somehow i could feather the gas just to keep it running, and was able to crawl home. when i drove down the street it seemed to run great! but if you stop and let it idle it has a really low idle and it shakes pretty good. its also smoky, also it somehow has made me loose power to my brakes. could i have realy screwed up my car that bad, or was something just ready to go? any help would be appreciated.