The inducer motor runs for 6-10 secs then goes off with no ignition. After 1 sec it starts again for 6-10 then off again with no ignition. This happens for about 1-2 minutes. If I turn thermostat down and wait 10-20 minutes and start it again sometimes it will start right up. I check the controller board red light and it is out even though furnace is running. If I pull panel and push on board connectors I can get the red light to flash normally. But that doesn't always mean the furnace will start right up. This seems to happen more in the mornings but it doesn't happen everyday.
Any ideas? Controller board shot? Loose connectors? Wire short? Something else?

I'd start with making sure all wires are connected and pressed in on the board. Make sure you have fresh batteries in the 'stat. Make sure the fuse is in tight.

You can also have bad bearings in the inducer motor and bad capacitors on the circuit board. Look for swollen capacitors on the circuit board-See YouTube for ways to test them. A new inducer motor is usually cheap. They corrode rapidly due to the acidic conditions they operate in. You should replace the entire assembly, fan with the motor, plus you should paint both with a good corrosion-resistant paint before installation. The factory paint does not last very long. You can get a very good professional spray paint at Home Depot that works very well. In some units I have even replaced the cheap unsealed bearings with sealed bearings on the motor and those have not failed for over ten years.

I don't know how proficient you are at troubleshooting or even if you have the tools or knowledge to do so, or even if you have been keeping a regular maintenance schedule with your unit. It may be well worth the house call fee ($50 bucks is what I typically have paid and that's applied to any work that has to be done) to have a trained technician with tools to inspect your system and give you a diagnosis of your problem and an estimate of repairs. Even if you decide to do it yourself at least then you will have identified the problem, and have a direction for the solution that will save you the time and trouble that guesswork and changing parts willy nilly will cost you.

If you don't have a manual, or ohmmeter, and understand how to use them, make a few calls and save yourself some headaches. To keep it real, your issue could be anything, or a combination of things. Let's start with your owner's manual... got one?

Trane XB90 Manuals (http://trane.manualnguide.com/manual-trane-xb90)

Here are some manuals: https://dl.dropboxusercontent.com/u/8010163/Carrier%20and%20Heater%20manuals.zip
https://dl.dropboxusercontent.com/u/8010163/HVAC_ELEC-2.mp4
https://dl.dropboxusercontent.com/u/8010163/Electrical%20Theory%20and%20Diagnosis%20of%20Major %20Appliances%20Service%20Manual.pdf
https://dl.dropboxusercontent.com/u/8010163/HVAC_Troubleshooting.pdf
You definitely need to know electrical diagnosis, but after you learn this and get a good meter you will usually find that most problems are easy. Unfortunately, many HVAC techs have gotten out of the trade due to so many EPA regulations that took away our best refrigerants and made new ones too expensive, all due to Marxist doctrines-most people should not have heating and cooling, according to their theories, only the elite (Democrats) due to "Climate Change." So, you best learn how to fix things yourself.