ok changed out the o2s still misfires and on top of that my alt went bad luckly had warranty changed out in an hour but still back fires .what about the iac or map sensor they are the original ones of my mtb

 

I would check the IAC and possibly the cam pos. sensor

 

could the can position sensor make the car back fire ,and how hard is it to replace

 

i mean cam position sensor.

 

That would usually result in a no start situation.

 

The car will run if the cam pos. sensor is bad, just not the crank sensor.

 

I've changed out the iac ,map,tried to clean out the egr ,tb,also changed the cam pos.sensor .I think i have solved the back fire problem i won't know until later after the car has sat for a while but still have a mis problem what controls the fuel air mix or maybe just needs to be re timed if possable .I'm not ready to throw in the towel just yet after everything ive changed and relpaced it would be a shame to do just that .any suggestions would be greatly appreciated.