I've looked for the rollout switch and can't seem to find it or knows what it looks like I've read some of the ?'s and having the same problem it is blinking 3/3 so I changed the filter etc etc BUT WHERE IS THE ROLLOUT SWITHCH am I just blind any help

Why do you need to find the rollout switch? What kind make/model unit do you have? If you don't know what it looks like I wouldn't recommend you mess with it. Gas units can be dangerous and should only be serviced by trained service technicians. Any poorly operating gas furnace could produce deadly carbon monoxide gas.

If you think a rollout switch is causing you problems it is probably because the rollout switch is doing what it is suppose to do in the first place and that is to turn your furnace off the flame rolls out the front of the burners. And like JackT said about this needs the service of a person that is knowledgeable in bad heat exchangers.