have you change the coolent temp sensor? i had a swift that would run fine until hitting running temp then it spudder out and would not start till it cooled off.

How about we start with - what codes does it give you?

The concept behind OBD is that does the diagnosis for you - use the information if it's available.

Now - let me ask you this - did you really change the crank sensor?  Wasn't that a lot of work to do on a suspicion?

Misfire codes can be of multiple sources, not just ignition caused, it can be a ignition issue or a rich fueling issue. A vacuum leak can also cause a misfire as well as a clogged cat/exhaust.

Age of O2 sensor is unknown that is an avenue that i have not explored as well as the cat. I am going to disconnect the cat tonight and maybe pick up an O2 sensor on the way home due to they are inexpensive and give that a shot. thanks again for all the help and ideas! Will keep you posted if any of that works!

just to let you know that wen i have removed my cat off my vitara, i now i got a engine light on, "evaporation leak" i think was the code. it wen on after i have removed it and replaced it with a piece of pipe. you said the o2 sensor is cheap, plz let us know the price  i never seen those go under 150$ yet new

Removing the cat will generate a catalyst efficiency failure code. This can be sidestepped by installing a secondary o2 sensor offset between the sensor and exhaust. this removes the sensor from direct contact with the exhaust flow causing it to think the cat is installed and working. Of course this is for off road use only.......
http://vibrantperformance.com/catalog/product_info.php?cPath=1022_1069&products_id=2009

Thanks for that link, talonxracer.  That was useful!  Been wondering about something like that.

LOL, yeah it is,,,what happens is that it creates a heated negative pressure chamber for the secondary sensor to sit in. Just like there is less oxygen when traveling to a higher altitude(lower barometric pressure) a negative pressure chamber reduces the pressure thusly reducing the oxygen content which is measured by the secondary sensor fooling the ECU into thinking there is a 100% functioning cat installed. The different dia orfices are used to dial in the proper negative pressure to fool the ECU.