Over the last couple weeks, my van (with a tiico engine) has died about half a dozen times. Its only done it after driving for at least an hour, leading me to believe its something temperature related. Once it dies, It cranks over fine, but no start. Then, after about five minutes, it starts right up, and will run for a while (the longer it sits, the longer it runs). The temperature gage never rises above where it is normally. No unusual fault codes on the vag-com. Replaced the fuel filter, and checked the lines in the engine compartment, doesn't seem like thats the probelm. On short trips, you'd never know anything was wrong.

Think this might be a bad coil? its about the only thing I didn't replace when I put the engine in. yeah, I know, check for spark when it won't start. haven't done that, only 'cause i've been by myself each time its happened. any other ideas?

thanks, 
jeff