Most car washes spray water up underneath to clean off road salt. That water will get onto electrical wiring and connectors under the hood just like rain can splash up there only with a lot more force. The first problem is ignition system wiring, meaning spark plug wires. Regardless which engine you have, there are no spark plugs wires to short from water infiltration. There's a separate ignition coil for each cylinder. If some water happened to sneak in where it can short out the spark, the arcing will leave a carbon track behind which will also short the spark voltage rather than let it fire the spark plug. That won't go away by just drying it.
More likely water got forced into a connector and affected some sensor signals. All manufacturers use weatherpack connectors to prevent rain water from getting in by the terminals but the force of a car wash might get some water in there. Typically it won't dry out and will lead to corrosion of electrical terminals and worse problems.
I'd start by asking exactly what was wet that caused the problem, and if it can be sealed better to prevent future problems. Also, the vehicle is seven years old so you might look for rubber seals that have dried out and aren't sealing properly. Poor running after a car wash might be warning you that something similar could happen in a rain storm and leave you stranded on the side of the road.
Tuesday, April 24th, 2012 AT 9:43 PM