Here are the details. Goodman GMS80somethingsomething with 2 burners and the blower on the bottom. Furnace would start up, start the exhaust, light the burners, and as soon as the main blower would come on, shutdown and start over.
After reading the post, and looking at a manual I found online for similar furnaces I checked the limit switches, and then I was able to ID the pressure switch for the exhaust vacuum pressure. It seems that it is a safety check system to make sure the exhaust is blowing/sucking enough. It was a circular plastic item a little bigger than a half dollar and about 1/2 an inch thick. It had a vacuum line going to it and two leads. I took the line off, and tested that it made clicking noises when I sucked on the line indicating that it was probably a working switch. Then I started the furnace while sucking on the line, and the furnace worked. This confirmed at the switch was working but not getting enough vacuum. I poked a long cotter pin into the hose barb on the exhaust housing and felt some kind of obstruction give way. After starting I put the lower panel back on, and started the furnace, the vacuum on the exhaust fan seemed to be a slightly louder whistle, and so I reattached the line, system is now functioning properly.