4 cyl. 3 weeks ago it died on the highway. Restarted but died again after about 10 minutes driving.. Dealer replaced ignition switch; it was a little loose. Died on the highway again today. It restarted, then died after sitting at idle for 10 minutes. Had it towed in. Wondering what the dealer will say this time. Any ideas on what is causing this?

 

Many things can cause engines to quit. The computer relay, fuel pump relay, engine and body grounds, loose connections, corrosion on the battery cables, and more can interrupt the ignition or fuel system.
Check for those, and listen for the fuel pump, mounted in the tank underneath the body about where the rear seat is located, to run when you turn the key from off to on. It should run and pressurize the injectors, about 3-5 seconds, then shut off. The dash lights should light up when the key is turned also. If you have those, I'd check under the hood for loose grounds on the engine and body, and loose battery cables. Additionally you can inspect the main power box mounted near the battery for loose connections, relays, and corrosion.
tom