My Tec2 used to do that at times also. I would get out, pull both green connectors out, then push them back in and it would start.
I also had a prob one time with the MAT sensor pin sticking out of the TEC unit itself. It was corroded inside the Tec and once I sent it in and got it back, no more problems...
I ended up just putting in a Tec3r a couple months ago.