We have a 1997 Acura TL 2.5L that will not start up after warmed up. It has nothing to do with weather, will do it on hot or cold days. The car will turn over but will not run until it sits at least 3+ hours. I cleaned the EGR valve and checked ports for any cloggage and it appears the intake manifold gasket is not installed backwards. The car does not idle or run rough either. This one is a bit of a stumper, any ideas?