The blower kicks in for a couple of minutes then shuts down, probably because it will not ignite. Any idea what the cause could be?

FYI that is a Tempstar furnace. I need to know more. Draft inducer runs, or blower motor. Do burners ever light? If I'm not mistaken that furnace uses an intermittant pilot, does the pilot light?
Click here for different types of ignition, it helps me know what controls you may have.

I am pretty sure that it is an intermittent pilot. It will ignite if I power it off after a cycle and let it sit for about a minute before powering it up. It will last for about 2 minutes. I just had someone look at it who replaced the pilot, it didn't change anything.

Do the burners ever ignite? Did you try to clean the flame sensor/ignitor probe?

I called the serviceman back in and powered it off for about 5 minutes. This time it stayed ignited. They cleaned out the pipe with a float in it and thought that may be the problem. We'll see. But its' been on for about 30 minutes now. Thanks for your help.